JP2016222156A - Control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device which, while assisting start of an engine by a motor, can suppress the maximum output required for the motor.SOLUTION: A hybrid ECU 26 has a raising control execution part 265 for executing motor rotation speed raising control of increasing the rotation speed of a motor generator MG to a predetermined rotation speed, and a lowering control execution part 266 for executing motor rotation speed lowering control of engaging a first clutch CL1 and reducing the rotation speed of the motor generator MG from the predetermined rotation speed after execution of the motor rotation speed raising control and before transition timing. An MG rotation speed determination part 264 determines the predetermined rotation speed such that the output of the motor generator MG at the end of execution of the motor rotation speed raising control becomes almost the same with the output of the motor generator MG at the start of execution of the motor rotation speed lowering control.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a control device for a drive system that transmits power generated by an engine and a motor to an axle of a vehicle.

  Due to increasing environmental awareness, the shift from automobiles that generate power using fossil fuels such as gasoline to electric vehicles that generate power using electric power is being promoted. As one form of automobile in such a transition process, an automobile called a hybrid vehicle using an engine and a motor as power sources has become widespread.

  Patent Document 1 listed below includes a first clutch (engine clutch) that is engaged and released between an engine and a motor, and a second clutch (starting clutch) that is engaged and released between a motor and an axle. A hybrid vehicle is described. The vehicle can travel by generating torque with a motor that receives power supply from a battery in a state in which combustion of fuel in the engine is stopped.

  In the vehicle described in Patent Document 1 below, when shifting to a travel mode in which torque is generated by the engine during execution of the travel mode using only the torque generated by the motor, first, the rotational speed of the motor is increased to a predetermined rotational speed. Let Thereafter, the vehicle starts combustion of fuel in the engine by engaging the first clutch and transmitting torque from the motor to the engine. That is, a smooth engine start is realized by using a motor that generates torque for running as a starter motor that assists engine start (start of fuel combustion).

JP 2000-255285 A

  However, the vehicle described in Patent Document 1 has not been sufficiently considered with respect to the output required for the motor when starting the engine. In other words, when the engine is started, the motor needs to generate a large torque, and accordingly, the maximum output (maximum value of the product of the motor torque and the rotational speed) required for the motor also increases. It is necessary to prepare a battery with a large maximum output. For this reason, there existed the subject of causing the enlargement of a battery or the increase in manufacturing cost.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a control device capable of suppressing the maximum output required for the motor while assisting the engine start by the motor. There is to do.

  In order to solve the above problems, a control device according to the present invention is a control device for a drive system (10) that transmits power generated by an engine (EG) and a motor (MG) to an axle (16) of a vehicle (100). (26) The drive system includes an engine shaft (11) for transmitting power generated by the engine, and a first shaft (MG1) and a second shaft (MG2) for transmitting power generated by the motor. And a first clutch (CL) 1 provided between the engine shaft and the first shaft for fastening and releasing, and provided between the second shaft and the axle for fastening and releasing. A second clutch (CL2); and a battery (21) for supplying electric power to the motor. The control device includes a first travel mode execution unit (261) that executes a first travel mode in which power is generated by the motor in a state where combustion of fuel in the engine is stopped, and combustion of fuel in the engine. A second traveling mode execution unit (262) for executing a second traveling mode for generating power, a motor rotational speed determining unit (264) for determining the rotational speed of the motor, and the second traveling mode from the first traveling mode. Prior to the transition timing to the travel mode, a pull-up control execution unit (265) that executes a motor speed-up control for increasing the motor speed to a predetermined speed with the first clutch released. After the execution of the motor rotation speed increase control and before the transition timing, the first clutch is engaged and the rotation speed of the motor is changed from the predetermined rotation speed. A drop control execution unit that executes the motor speed drop control to low as the (266), the. The motor rotation speed determination unit is configured so that the output of the motor at the end of execution of the motor rotation speed increase control is substantially the same as the output of the motor at the start of execution of the motor rotation speed decrease control. A predetermined rotation speed is determined.

  In the motor rotational speed pull-up control, the output required for the motor increases as the predetermined rotational speed increases. However, if the predetermined rotational speed increases, the motor at the end of the execution of the motor rotational speed increase control has a large kinetic energy. Therefore, the output required for the motor in the subsequent motor rotational speed decrease control is There is a tendency that the larger the predetermined number of rotations, the smaller the number of rotations becomes.

  Therefore, in the present invention, in the present invention, the predetermined output speed is set so that the output of the motor at the end of execution of the motor speed increase control and the output of the motor at the start of execution of the motor speed decrease control are substantially the same. To decide. Thus, it is possible to suppress the maximum output required for the motor while assisting the engine start by the motor.

  ADVANTAGE OF THE INVENTION According to this invention, the control apparatus which can suppress the maximum output required for a motor can be provided, assisting engine start by a motor.

It is a mimetic diagram showing a hybrid vehicle carrying a hybrid ECU concerning an embodiment of the present invention. It is a time chart which shows the example of control by hybrid ECU of FIG. It is explanatory drawing explaining the determination method of pulling-up rotation speed. It is a flowchart which shows the flow of the process by hybrid ECU of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In order to facilitate the understanding of the description, the same constituent elements in the drawings will be denoted by the same reference numerals as much as possible, and redundant description will be omitted.

  First, a schematic configuration of a drive system 10 equipped with a hybrid ECU (Electronic Control Unit) 26 according to an embodiment of the present invention and a hybrid vehicle 100 equipped with the drive system 10 will be described with reference to FIG.

  The drive system 10 includes an engine EG, a first clutch CL1, a motor generator MG, a second clutch CL2, an automatic transmission 13, a differential 15, an axle 16, and wheels 17.

  The engine EG is an internal combustion engine that generates torque (power) using gasoline as fuel. The engine EG controls a valve opening degree of a throttle valve (not shown) based on a control signal received from the engine ECU 27. The engine EG has an engine shaft 11 that transmits the generated torque.

  First clutch CL1 is provided between engine shaft 11 of engine EG and first shaft MG1 of motor generator MG. The first clutch CL1 is a wet multi-plate clutch capable of continuously controlling the flow rate and pressure of hydraulic oil with a proportional solenoid. The first clutch CL <b> 1 is controlled to be engaged and disengaged including slip engagement by a control oil pressure generated by a pump (not shown) based on a control signal received from the transmission ECU 29.

  Motor generator MG is a synchronous motor generator in which a permanent magnet is embedded in a rotor and a stator coil is wound around a stator. Motor generator MG has a first shaft MG1 extending to the engine EG side and a second shaft MG2 extending to the automatic transmission 13 side. The first axis MG1 and the second axis MG2 are provided to rotate in synchronization. Motor generator MG is controlled by applying a three-phase alternating current generated by inverter 20 based on a control signal received from MG-ECU 28.

  The motor generator MG functions as an electric motor that is driven to rotate by receiving power supplied from the battery 21 and generates torque (power). Further, when the rotor is rotated by an external force received from the first shaft MG1 or the second shaft MG2, the motor generator MG functions as a generator that generates electromotive force at both ends of the stator coil and charges the battery 21. It can also be made.

  Electric power is transferred between battery 21 and motor generator MG through inverter 20. The inverter 20 is a converter that converts DC power into AC power or AC power into DC power. Inverter 20 operates based on a control signal received from MG-ECU 28.

  The second clutch CL <b> 2 is provided between the second shaft MG <b> 2 of the motor generator MG and the input shaft 131 of the automatic transmission 13. The second clutch CL2 is a wet multi-plate clutch that can continuously control the flow rate and pressure of hydraulic oil with a proportional solenoid. The second clutch CL2 is controlled to be engaged and disengaged including slip engagement by a control oil pressure generated by a pump (not shown) based on a control signal received from the transmission ECU 29.

  The automatic transmission 13 is a transmission that automatically switches the gear ratio in a plurality of stages according to the speed of the hybrid vehicle 100 (hereinafter also simply referred to as “vehicle speed”), the accelerator opening, and the like. The second clutch CL <b> 2 is not newly added as a dedicated clutch, but uses some frictional engagement elements among a plurality of frictional engagement elements that are engaged at each speed of the automatic transmission 13. The output shaft 132 of the automatic transmission 13 is connected to the wheel 17 via the differential 15 and the axle 16. When a continuously variable transmission is provided, the clutch provided in the forward / reverse switching mechanism may be used as the second clutch CL2, and the configuration of the second clutch CL2 is not particularly limited.

  Next, the hybrid ECU 26 according to the embodiment of the present invention will be described. The hybrid ECU 26 is a computer that comprehensively controls the entire hybrid vehicle 100. The hybrid ECU 26 includes an engine ECU 27 that controls the operation of the engine EG, an MG-ECU 28 that controls the rotation of the motor generator MG by controlling the operation of the inverter 20, the automatic transmission 13, the first clutch CL1, and the second clutch. It is electrically connected to a transmission ECU 29 that controls the operation of CL2. The hybrid ECU 26 transmits and receives control signals and data signals to and from the engine ECU 27, MG-ECU 28, and transmission ECU 29, so that the engine EG, the motor generator MG, the automatic transmission 13, the first clutch CL1, and the second clutch CL2. To control.

  In the present application, “electrically connected” is not limited to the state of being connected by wire, and may include a state in which communication is possible with each other wirelessly.

  The hybrid ECU 26 is electrically connected to various sensors such as an accelerator sensor 22, a shift switch 23, a brake switch 24, a rotational speed sensor 25, an engine rotational speed sensor 30, and an MG rotational speed sensor 31. ing. The accelerator sensor 22 is a device that detects an operation of an accelerator pedal (not shown). The shift switch 23 is a sensor that detects the position of a shift lever (not shown) of the hybrid vehicle 100, such as “P” (parking: parking), “R” (reverse: reverse), “D” (drive: forward), etc. is there. The brake switch 24 is a device that detects an operation of a brake (not shown). The rotational speed sensor 25 is a device that detects the rotational speed of the output shaft 132 of the automatic transmission 13. The engine rotation speed sensor 30 is a device that is attached to the engine EG and detects the rotation speed of the engine EG. The MG rotation speed sensor 31 is a device that is attached to the motor generator MG and detects the rotation speed of the motor generator MG. The hybrid ECU 26 detects the driving state of the hybrid vehicle 100 by reading output signals from various sensors and switches. For example, the hybrid ECU 26 detects the vehicle speed of the hybrid vehicle 100 based on the output signal of the rotational speed sensor 25.

  FIG. 1 shows the inside of the hybrid ECU 26 as a functional control block diagram. A part or all of the hybrid ECU 26 is configured by an analog circuit or a digital processor. In any case, a functional control block is configured in the hybrid ECU 26 in order to fulfill the function of outputting a control signal based on the received signal.

  Note that the software module incorporated in the analog circuit or digital processor constituting the hybrid ECU 26 does not necessarily have to be divided into the control blocks shown in FIG. 1, and is configured to function as a plurality of control blocks. However, it may be further subdivided. A person skilled in the art can appropriately change the actual configuration inside the hybrid ECU 26 as long as the processing described later can be executed.

  The hybrid ECU 26 includes a first travel mode execution unit 261, a second travel mode execution unit 262, an acceleration request determination unit 263, an MG rotation speed determination unit 264, a pulling control execution unit 265, and a descent control execution unit 266. And have.

  First traveling mode execution unit 261 is a portion that executes a “first traveling mode” in which torque is generated by motor generator MG while fuel combustion in engine EG is stopped. That is, first traveling mode execution unit 261 stops the supply of fuel into a plurality of cylinders (not shown) of engine EG and supplies power to motor generator MG to generate torque.

  The second travel mode execution unit 262 is a part that executes a “second travel mode” in which the engine EG burns fuel to generate torque. In other words, the second travel mode execution unit 262 supplies fuel into the cylinder of the engine EG, and sparks an air-fuel mixture composed of fuel and air in the cylinder to burn the fuel. As a result, the so-called intake stroke, compression stroke, combustion stroke, and exhaust stroke are repeatedly performed in different phases in each cylinder of the engine EG, and torque is generated.

  The acceleration request determination unit 263 is a part that determines whether or not there is a request for acceleration from the driver to the hybrid vehicle 100. Specifically, the acceleration request determination unit 263 determines whether or not there is an acceleration request from the driver by performing a predetermined calculation based on a signal received from the accelerator sensor 22.

  MG rotation speed determination unit 264 is a part that determines the rotation speed of motor generator MG. Specifically, MG rotation speed determination unit 264 performs a predetermined calculation based on signals received from various sensors, thereby supplying the rotation speed of motor generator MG and the motor generator MG corresponding to the rotation speed. Determine the power.

  The pull-up control execution unit 265 increases the rotation speed of the motor generator MG in the state where the first clutch CL1 is released, prior to the transition timing from the first travel mode to the second travel mode. This is the part that executes “control”.

  The descending control execution unit 266 engages the first clutch CL1 and sets the rotational speed of the motor generator MG after the execution of the motor rotational speed increase control and before the transition timing from the first traveling mode to the second traveling mode. This is a part for executing “MG rotational speed drop control” to decrease.

  Subsequently, an example of control according to the present embodiment will be described with reference to FIGS. 2 and 3. In FIG. 2, an example of control according to the present embodiment is indicated by a solid line, while a comparative example is indicated by a broken line. In the following, for the sake of simplicity, it will be described in detail that the hybrid ECU 26 collectively performs the processes performed by the respective parts such as the first travel mode execution unit 261 of the hybrid ECU 26.

[This embodiment]
First, an example of control according to the present embodiment will be described. Until time t1, the hybrid ECU 26 executes the first travel mode and causes the hybrid vehicle 100 to travel. At this time, the motor generator MG is driven to rotate by receiving electric power, and is rotated at the rotation speed N1 together with the output shaft 132 of the automatic transmission 13 by the second clutch CL2 being engaged. On the other hand, since the control hydraulic pressure of the first clutch CL1 is zero, the first clutch CL1 is released, and the engine EG in which the combustion of fuel is stopped is also zero.

  Further, until time t1, motor generator MG generates torque T1 by being rotationally driven. Thus, the output of motor generator MG up to time t1 (the product of the rotational speed and torque of motor generator MG) is W1.

  When it is determined at time t1 that there is an acceleration request from the driver (accelerator depression amount increases) and the required torque exceeds a predetermined threshold value, the hybrid ECU 26 executes the MG speed increase control. Start. Specifically, hybrid ECU 26 increases the rotation speed of motor generator MG. As the rotation speed of motor generator MG starts increasing, the torque generated by motor generator MG increases from T1 to T4. Further, the output of motor generator MG also increases to W3, and further increases with the rotational speed.

  Further, at time t1, the hybrid ECU 26 increases the control hydraulic pressure of the first clutch CL1 to P4. This is to increase the control oil pressure and fill the cylinder (not shown) of the first clutch CL1 with control oil as a preparation for fastening the first clutch CL1 later.

  At time t3, the hybrid ECU 26 decreases the control hydraulic pressure of the first clutch CL1 to P2. That is, when the filling of the control oil into the cylinder of the first clutch CL1 is completed at time t3, the control oil pressure is decreased, and the system waits until the behavior of the control oil in the cylinder becomes stable.

  At time t4, the hybrid ECU 26 finishes executing the MG rotation speed increase control. The rotational speed Anf of the motor generator MG at the end of execution of this MG rotational speed pull-up control is N3. That is, the hybrid ECU 26 increases the rotational speed by the pulling-up rotational speed ΔNa by the MG rotational speed pull-up control from the time t1 to the time t4.

  At the time t4, the torque generated by the motor generator MG decreases from T4 to T3 with the end of execution of the MG rotation speed increase control. Further, the output Awfup of the motor generator MG at time t4 when the execution of the MG rotation speed increase control ends is W5, but the output also decreases from W5 to W3 as the torque of the motor generator MG decreases. After time t4, hybrid ECU 26 maintains the rotational speed of motor generator MG at N3.

  At time t5, the hybrid ECU 26 starts executing the MG rotation speed reduction control. The rotation speed Bnf of the motor generator MG at the start of execution of this MG rotation speed decrease control is N3.

  Further, the hybrid ECU 26 estimates that the behavior of the control oil in the cylinder of the first clutch CL1 has stabilized after a sufficient time has elapsed since the control hydraulic pressure of the first clutch CL1 was reduced to P2 at time t3. At time t5, the control hydraulic pressure of the first clutch CL1 is increased to P3. Thus, first clutch CL1 starts slip engagement, and torque is transmitted from first shaft MG1 of motor generator MG to engine shaft 11 of engine EG. Accordingly, the rotational speed of engine EG gradually increases.

  Furthermore, when slip engagement of the first clutch CL1 is started, the torque generated by the motor generator MG increases to T5, and thereafter maintained at T5. Hybrid ECU 26 starts decreasing the rotational speed of motor generator MG based on the increase in torque in motor generator MG. Further, the output Bwfdw of the motor generator MG at the start of the execution of the MG rotation speed reduction control becomes W5 which is the same as the output Awfup at the end of the execution of the MG rotation speed increase control described above, but thereafter the rotation speed decreases. It decreases with. In this example, the output Bwfdw is W5 which is the same as the output Awfup. However, the output Bwfdw does not necessarily need to be completely the same, and may be substantially the same.

  At time t6, the hybrid ECU 26 starts executing the second travel mode and causes the hybrid vehicle 100 to travel. Specifically, spark ignition is performed in the cylinder of engine EG, and engine EG is started (fuel combustion is started). After time t6, the rotational speed of the engine EG further increases. At time t6, the rotational speed of motor generator MG decreases to N2, and thereafter is maintained at N2.

  Further, at time t6, the hybrid ECU 26 reduces the control hydraulic pressure of the first clutch CL1 to P1, and relaxes the engagement of the first clutch CL1. Thereby, transmission of torque from first shaft MG1 of motor generator MG to engine shaft 11 of engine EG is relaxed, and engine EG autonomously increases the rotational speed by the combustion of fuel. In addition, at time t6, the control hydraulic pressure of the first clutch CL1 may be set to zero and the first clutch CL1 may be released.

  Furthermore, at time t6, engine EG starts combustion of fuel and generates torque, so that torque generated by motor generator MG decreases from T5. Along with this, the output of motor generator MG also decreases.

  When the rotational speed of engine EG becomes N2 which is the same as the rotational speed of motor generator MG at time t7, hybrid ECU 26 increases the control hydraulic pressure of first clutch CL1. As a result, first clutch CL1 is engaged, and hybrid vehicle 100 travels with torque generated by both engine EG and motor generator MG.

  Here, with reference to FIG. 3, a method for determining the pulling rotation speed ΔNa will be described. The pulling rotation speed ΔNa is determined by the MG rotation speed determination unit 264 of the hybrid ECU 26 described above.

  FIG. 3 shows the characteristics of the motor generator MG. Specifically, an output Awup that is an output of the motor generator MG at the end of execution of the MG rotation speed increase control, an output Bwfdw that is an output of the motor generator MG at the start of execution of the MG rotation speed reduction control, and the rotation A relationship with the pulling-up rotational speed ΔN, which is an increase in the rotational speed of the motor generator MG from the number N1, is shown. Data relating to this characteristic is stored in a memory (not shown) of the hybrid ECU 26.

  As shown in FIG. 3, the output Awfup has a tendency to increase with the pulling-up rotational speed ΔN. This is because the torque required for rotationally driving the motor generator MG in the MG rotational speed pull-up control increases as the pulling rotational speed ΔN increases.

  On the other hand, the output Bwfdw, which is the output of the motor generator MG at the start of execution of the MG rotation speed decrease control, tends to decrease generally as the pulling rotation speed ΔN increases. This is because as the pulling-up rotational speed ΔN increases, the motor generator MG has a larger kinetic energy due to the execution of the MG rotational speed lowering control, and the kinetic energy can be used in the subsequent MG rotational speed lowering control. This is because it can. In other words, as the pulling-up rotational speed ΔN increases, the motor generator MG can use a larger inertia in the MG rotational speed lowering control, so the output required for the motor generator MG in the MG rotational speed lowering control is reduced. be able to.

  If the hybrid ECU 26 determines the pulling-up rotational speed to be ΔNb shown in FIG. 3, the output Awfup that is the output of the motor generator MG at the end of execution of the MG rotational speed pull-up control is WA. On the other hand, output Bwfdw, which is the output of motor generator MG at the start of execution of MG rotation speed reduction control, becomes WD, which is larger than WA. Therefore, in this case, the maximum output required for the motor generator MG is WD, and it is necessary to select the battery 21 that can support the maximum output WD.

  Further, if the hybrid ECU 26 determines the pulling rotation speed to be ΔNc shown in FIG. 3, the output Awup, which is the output of the motor generator MG at the end of execution of the MG rotation speed pulling control, becomes WC. On the other hand, output Bwfdw, which is the output of motor generator MG at the start of execution of MG rotation speed reduction control, is WB, which is smaller than WC. Therefore, in this case, the maximum output required for the motor generator MG is WC, and it is necessary to select the battery 21 that can support the maximum output WC.

  Therefore, the hybrid ECU 26 determines ΔNa corresponding to the intersection of the output Awfup characteristic line and the output Bwfdw characteristic line as the pulling-up rotational speed in order to reduce the maximum output required for the motor generator MG as much as possible. To do. That is, this pulling-up rotational speed ΔNa is an increase in the rotational speed of motor generator MG in the MG rotational speed pull-up control. By determining the pulling-up rotational speed to be ΔNa, the maximum output required for the motor generator MG becomes W5 smaller than WC and WD, so that the maximum output required for the battery 21 can be minimized. .

[Comparative example]
Next, a comparative example will be described. Similarly to the embodiment, in the comparative example, when there is an acceleration request from the driver at time t1 and it is determined that the required torque exceeds a predetermined threshold, the hybrid ECU 26 increases the rotation speed of the motor generator MG. Is. As the rotation speed of motor generator MG starts increasing, the torque generated by motor generator MG increases from T1 to T4. Further, the output of motor generator MG also increases to W3, and further increases with the rotational speed.

  In the comparative example, as indicated by a broken line in FIG. 2, the increase is stopped at time t2 when the rotation speed of the motor generator MG increases to N2. At time t2, the torque generated by motor generator MG decreases to T2, and accordingly, the output also decreases to W2. After time t2, motor generator MG rotates at rotation speed N2.

  At time t5, the comparative example increases the control hydraulic pressure of the first clutch CL1 to P3 as in the embodiment. Thus, first clutch CL1 starts slip engagement, and torque is transmitted from first shaft MG1 of motor generator MG to engine shaft 11 of engine EG. Accordingly, the rotational speed of engine EG gradually increases.

  Further, at time t5, the torque generated by the motor generator MG in the comparative example is T6, which is larger than T5 of the embodiment. That is, in the comparative example, since the kinetic energy possessed by motor generator MG at time t5 is smaller than that of the embodiment, it is necessary to newly generate a large torque at time t5. For this reason, the output Bw of the motor generator MG of the comparative example at time t5 is also W6 which is larger than W5 of the embodiment. Further, the rotation speed Bn of the motor generator MG at time t5 is maintained at N2.

  As described above, in this comparative example, the maximum output required for the motor generator MG is W6, which is larger than that of the above-described embodiment (W5). Therefore, in this comparative example, it is necessary to prepare the battery 21 having a larger maximum output as compared with the embodiment, which may increase the size of the battery or increase the manufacturing cost.

  Subsequently, a flow of processing executed in the hybrid ECU 26 of the present embodiment will be described with reference to FIG.

  First, the hybrid ECU 26 determines whether or not the driver's required torque exceeds a predetermined threshold value in step S1 of FIG. That is, the hybrid ECU 26 determines whether or not the torque corresponding to the acceleration requested by the driver cannot be generated only by the motor generator MG, and it is necessary to start the engine EG. If it is determined that the driver's required torque exceeds the threshold (S1: Yes), the hybrid ECU 26 proceeds to the process of step S2.

  Next, the hybrid ECU 26 sets the pulling-up rotational speed ΔN of the motor generator MG in step S2. As described above, the hybrid ECU 26 sets the pulling-up rotational speed ΔN so that the maximum output required for the motor generator MG is minimized based on the characteristics of the motor generator MG shown in FIG.

  Next, hybrid ECU 26 controls the rotation speed of motor generator MG in step S3. In other words, hybrid ECU 26 determines the number of rotations of motor generator MG to be N1 at the start of execution of MG rotation number increase control plus the increase number of rotations ΔN, and then increases the MG rotation number. In the control, the rotational speed of the motor generator MG is appropriately controlled, for example, by increasing the rotational speed of the motor generator MG.

  Next, the hybrid ECU 26 controls the second clutch CL2 in step S4. That is, the hybrid ECU 26 adjusts the vehicle speed of the hybrid vehicle 100 as appropriate by adjusting the transmission of torque from the motor generator MG to the axle 16 by slip-engaging the second clutch CL2.

  Next, the hybrid ECU 26 starts the engagement of the first clutch CL1 in step S5. Thus, torque can be transmitted from first shaft MG1 of motor generator MG to engine shaft 11 of engine EG, and the rotational speed of engine EG can be gradually increased to assist in starting engine EG.

  As described above, in the present embodiment, the output Awfup of the motor generator MG at the end of execution of the MG rotation speed increase control and the output Bwfdw of the motor generator MG at the start of execution of the MG rotation speed reduction control are substantially the same. Each rotation number is determined so that it becomes. Thus, it is possible to suppress the maximum output required for the motor generator MG while assisting the start of the engine EG by the motor generator MG.

  Further, in the present embodiment, the lowering control execution unit 266 increases the rotational speed of the engine EG by engaging the first clutch CL1, and after the fuel combustion in the engine EG starts, the first clutch CL1 is engaged. Relax or release the first clutch CL1. As a result, engine EG rotates with the torque transmitted from motor generator MG at the beginning of the start, while the rotation speed is increased with the torque generated by the combustion of fuel, not with the torque transmitted from motor generator MG in the late start. increase. Therefore, the maximum output required for motor generator MG can be further reduced, and the maximum output required for battery 21 can be reduced.

  In the present embodiment, lowering control execution unit 266 starts to reduce the rotational speed of motor generator MG based on the increase in torque in motor generator MG. The number of rotations of motor generator MG is preferably started to decrease based on the fact that first clutch CL1 is securely engaged, but the engagement is detected based on the control oil pressure in the cylinder of first clutch CL1. Has high technical difficulty. On the other hand, in the present embodiment, since it can be estimated that the first clutch CL1 is engaged based on the increase in the torque in the motor generator MG, a decrease in the rotational speed of the motor generator MG is started based on this. Thus, the same effect can be obtained.

  The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. In other words, those specific examples that have been appropriately modified by those skilled in the art are also included in the scope of the present invention as long as they have the characteristics of the present invention. Each element included in each of the specific examples described above and their arrangement, material, condition, shape, size, and the like are not limited to those illustrated, and can be appropriately changed.

10: Drive system 11: Engine shaft 16: Axle 21: Battery 26: Hybrid ECU (control device)
100: Hybrid vehicle (vehicle)
261: 1st driving mode execution part 262: 2nd driving mode execution part 264: MG rotation speed determination part (motor rotation speed determination part)
265: Pull-up control execution unit 266: Lowering control execution unit CL1: First clutch CL2: Second clutch EG: Engine MG: Motor generator (motor)
MG1: First axis MG2: Second axis

Claims (3)

A control device (26) of a drive system (10) for transmitting power generated by an engine (EG) and a motor (MG) to an axle (16) of a vehicle (100),
The drive system is
An engine shaft (11) for transmitting power generated by the engine;
A first shaft (MG1) and a second shaft (MG2) for transmitting power generated by the motor;
A first clutch (CL) 1 provided between the engine shaft and the first shaft for fastening and releasing;
A second clutch (CL2) provided between the second shaft and the axle for fastening and releasing;
A battery (21) for supplying electric power to the motor,
The controller is
A first travel mode execution unit (261) that executes a first travel mode in which power is generated by the motor in a state where combustion of fuel in the engine is stopped;
A second travel mode execution unit (262) for executing a second travel mode for generating power by burning fuel in the engine;
A motor rotation number determination unit (264) for determining the rotation number of the motor;
Prior to the transition timing from the first travel mode to the second travel mode, a motor speed increase control for increasing the motor speed to a predetermined speed with the first clutch opened is executed. A pull-up control execution unit (265);
Lowering control for executing motor rotational speed drop control for engaging the first clutch and reducing the rotational speed of the motor from the predetermined rotational speed after the execution of the motor rotational speed raising control and before the transition timing. An execution unit (266),
The motor rotation speed determination unit is configured so that the output of the motor at the end of execution of the motor rotation speed increase control is substantially the same as the output of the motor at the start of execution of the motor rotation speed decrease control. A control device that determines a predetermined number of revolutions.   The lowering control execution unit increases the number of revolutions of the engine by engaging the first clutch, and after the combustion of fuel in the engine starts, relaxes the engagement of the first clutch or disengages the first clutch. The control device according to claim 1, wherein the control device is opened.   The control device according to claim 1, wherein the descent control execution unit starts a decrease in the rotation speed of the motor based on an increase in torque in the motor.

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