Control device of hybrid vehicle

Abstract

To appropriately suppress occurrence of abnormal noise in accordance with operation states of a first rotary electric machine and a second rotary electric machine.SOLUTION: In a control device of a hybrid vehicle, an engine, a first rotary electric machine and a second rotary electric machine are connected to one another through a transmission mechanism. The transmission mechanism includes a gear whose movement direction is set depending on whether torque outputted by the second rotary electric machine changes from positive torque to negative torque or changes from negative torque to positive torque. The hybrid vehicle can run with torque outputted by the second rotary electric machine. The control device comprises a first rotary electric machine control part that when torque changes between a state in which the second rotary electric machine outputs positive torque and a state in which the machine outputs negative torque, in a state in which the engine stops and the hybrid vehicle runs with the torque outputted by the second rotary electric machine, executes control by which the gear is moved forehand in a direction in which the gear is moved as the torque outputted by the second rotary electric machine changes by operating the first rotary electric machine.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a control device for a hybrid vehicle. [Background technology]

[0002] 2. Description of the Related Art Conventionally, in a hybrid vehicle in which an engine, a first rotating electric machine, and a second rotating electric machine are connected via a transmission mechanism including a gear train, there have been proposals for suppressing the generation of abnormal noise in the gear train (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-222088 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the gear train of the transmission mounted on the hybrid vehicle may generate abnormal noise due to various reasons. For example, depending on the operating conditions of the first rotating electric machine and the second rotating electric machine, it may be impossible to effectively suppress the generation of abnormal noise by simply applying the proposal in Patent Document 1.

[0005] Therefore, an object of the invention disclosed in this specification is to appropriately suppress the occurrence of abnormal noise depending on the operating states of the first rotating electric machine and the second rotating electric machine. [Means for solving the problem]

[0006] The above problem is achieved by a control device for a hybrid vehicle in which an engine, a first rotating electric machine, and a second rotating electric machine are connected via a transmission mechanism, the transmission mechanism including a gear whose direction of movement is determined depending on whether the torque output by the second rotating electric machine is a torque change from positive torque to negative torque or a torque change from negative torque to positive torque, the hybrid vehicle can run by the torque output by the second rotating electric machine, and the control device includes a first rotating electric machine control unit that, when the engine is stopped and the hybrid vehicle runs by the torque output by the second rotating electric machine, operates the first rotating electric machine and executes control to move the gear in advance in the direction of movement of the gear associated with the torque change of the second rotating electric machine when there is a torque change between a state in which the second rotating electric machine outputs positive torque and a state in which it outputs negative torque. Effect of the Invention

[0007] The invention disclosed in this specification can appropriately suppress the occurrence of abnormal noise depending on the operating states of the first rotating electric machine and the second rotating electric machine. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a configuration diagram of a hybrid vehicle including a control device according to an embodiment. [Diagram 2] FIG. 2 is a flowchart showing an example of control performed by the control device of the embodiment. [Diagram 3] FIG. 3 is a time chart showing an example of changes in the MG1 torque, the MG2 torque, and the required output in the control performed by the control device of the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. Some drawings may omit details, and some drawings may only show main components.

[0010] (Embodiment) [Hybrid vehicle] 1 is a diagram showing a schematic configuration of a hybrid vehicle (hereinafter simply referred to as “vehicle”) 10. The vehicle 10 includes a vehicle body 12 and a control device 60.

[0011] The vehicle body 12 includes an engine 14, a first rotating electric machine (hereinafter referred to as "MG1"), and a second rotating electric machine (hereinafter referred to as "MG2"). The engine 14 and MG2 function as a drive source for the vehicle 10. The engine 14, MG1, and MG2 are connected via a power distribution mechanism 19 that also functions as a speed change mechanism. The power distribution mechanism 19 includes a gear train 20. The gear train 20 is connected to drive wheels 36 via a differential gear mechanism 34. The vehicle body 12 includes drive wheels 36 on both the left and right sides, although the drive wheel on one side is omitted in FIG. 1. A drive circuit including an inverter and a power storage device are connected to the MG1 and MG2, but these are also omitted from FIG. 1.

[0012] The engine 14 is an internal combustion engine that serves as one of the drive sources of the vehicle 10. The type of engine and the number of cylinders are appropriately selected.

[0013] MG1 and MG2 are motor generators, each of which functions as a motor when power is supplied from a drive circuit (not shown) and functions as a generator when the vehicle 10 is driven by the engine 14 or when the vehicle 10 is braked. In this embodiment, MG1 functions mainly as a generator driven by the engine 14. MG2 functions mainly as a motor that drives the drive wheels 36. MG2 outputs positive torque when the vehicle 10 is accelerated. MG2 generates negative torque when the vehicle 10 is decelerated. MG2 generates a torque change between a state in which positive torque is output and a state in which negative torque is output as the vehicle 10 accelerates or decelerates. The torque change when the vehicle 10 accelerates is a change that transitions from negative torque beyond a state of 0 Nm to positive torque. The torque change when the vehicle 10 decelerates is a change that transitions from positive torque beyond 0 Nm to negative torque.

[0014] The power distribution mechanism 19 appropriately distributes the power used for generating electricity and the power used for driving the drive wheels 36 between the output of the engine 14, the input / output to the MG1, and the output of the MG2 according to the running state of the vehicle 10. The power distribution mechanism 19 includes a sun gear portion S1 and a ring gear R arranged concentrically with the sun gear portion S1. The power distribution mechanism 19 further includes a first carrier C1 that holds a pinion gear that meshes with the sun gear portion S1 and meshes with the ring gear R so that it can rotate and revolve. The sun gear portion S1 includes a sun gear S2 and a second carrier C2 arranged around the sun gear S2. The power distribution mechanism 19 is a planetary gear mechanism that performs a differential action with the sun gear portion S1, the ring gear R, the first carrier C1, the sun gear S2, and the second carrier C2 as rotating elements.

[0015] An engine output shaft 40 extending from the engine 14 is connected to the ring gear R via a flywheel damper 38. The engine output shaft 40 is a crankshaft. An output shaft of the MG1 is connected to the sun gear S2. An output shaft of the MG2 is connected to the ring gear R via an output gear 24, a reduction gear 26, a counter driven gear 28, and a counter drive gear 22. The output shaft of the MG2 is also connected to the ring gear R via the output gear 24, the reduction gear 26, a drive pinion gear 30, a differential ring gear 32, and a differential gear mechanism 34. These gears constitute a gear train 20. The gear train 20 is housed in the case 19a.

[0016] A parking gear 42 is connected to the engine output shaft 40.

[0017] Helical gears are used for each gear included in such a planetary gear mechanism and transmit torque. Helical gears have high strength because they can increase the tooth width. In addition, helical gears have a large meshing area, which is advantageous in terms of reducing gear noise. When transmitting torque, the helical gears move in the direction of their rotation axis. The direction of this movement differs depending on whether the input torque is positive torque or negative torque. The direction of movement of the gears included in the gear train 20 is determined depending on whether the torque output by the MG2 transitions from positive torque to negative torque or from negative torque to positive torque. For example, when the MG2 transitions from negative torque to positive torque, the sun gear portion S1 moves leftward in FIG. 1. As a result, if no measures are taken, the sun gear portion S1 and the case 19a collide at the location indicated by reference symbol P1 in FIG. 1. This causes abnormal noise. On the other hand, when the MG2 transitions from positive torque to negative torque, the sun gear portion S1 moves rightward in FIG. 1. As a result, if no measures are taken, gears will collide with each other at the location indicated by reference character P2 in Fig. 1. Also, the first carrier C1 will collide with the case 19a at the location indicated by reference character P3 in Fig. 1. This will cause abnormal noise.

[0018] The control device 60 controls the operation of each element, including the engine 14, MG1, and MG2, included in the vehicle 10. The control device 60 also executes abnormal noise generation suppression control to suppress the generation of abnormal noise in the gear train 20. The control device 60 includes an MG1 control unit 60a and an MG2 state acquisition unit 60b. The MG1 control unit 60a causes the MG1 to output a desired torque to suppress the generation of abnormal noise. The MG2 state acquisition unit 60b determines whether the state of the MG2 is a state that generates abnormal noise. The control device 60 is connected to a vehicle speed sensor 52 and an accelerator opening sensor 54. The vehicle speed sensor 52 measures the speed of the vehicle 10. The accelerator opening sensor 54 measures the accelerator opening. The control device 60 calculates a required output based on the speed and the accelerator opening.

[0019] [Noise suppression control] An example of the abnormal noise generation suppression control executed by the control device 60 will be described below with reference to FIGS.

[0020] In step S1, the control device 60 determines whether the engine 14 is stopped. That is, the control device 60 determines whether the vehicle 10 is in a driving mode in which the vehicle 10 runs with the torque of the MG2. The control device 60 selects the driving mode of the vehicle 10 based on the vehicle speed and the accelerator opening. For this reason, the control device 60 holds information on whether the engine 14 is stopped. The control device 60 makes the determination in step S1 based on the information it holds. The reason for determining whether the engine 14 is stopped is that, when the engine 14 is running, the sound of the engine 14 does not disturb the abnormal noise generated in the gear train 20. When the control device 60 makes a positive determination in step S1, the control device 60 proceeds to step S2. On the other hand, when the control device 60 makes a negative determination in step S1, the control device 60 ends the process.

[0021] In step S2, the control device 60 determines whether the vehicle speed of the vehicle 10 is low. The control device 60 acquires a threshold value for determining whether the vehicle speed is low in advance. If the measurement value of the vehicle speed sensor 52 is lower than the threshold value, the control device 60 makes a positive determination in step S2. The reason for determining whether the vehicle speed of the vehicle 10 is low is that if the vehicle speed is high, abnormal noise generated in the gear train 20 due to the running sound of the vehicle 10 is not noticeable. If the control device 60 makes a positive determination in step S2, the process proceeds to step S3. On the other hand, if the control device 60 makes a negative determination in step S2, the process ends.

[0022] In step S3, the control device 60 judges whether the absolute value of the torque generated by the MG2 is sufficiently large based on the information acquired by the MG2 state acquisition unit 60b. Specifically, the control device 60 judges whether the absolute value of the torque generated by the MG2 is larger than the absolute value of a first threshold value t1 set in advance. Here, the absolute values ​​are compared with each other so that the method can be applied to both cases when the vehicle accelerates and decelerates, as shown in FIG. 3. The magnitude of the torque generated by the MG2 is judged because if the torque is small, abnormal noise is unlikely to occur in the gear train 20. The judgment in step S3 is performed to exclude such a case. When the control device 60 judges in step S3 as positive, the control device 60 proceeds to step S4. On the other hand, when the control device 60 judges in step S3 as negative, the control device 60 ends the process. In FIG. 3, the part related to the judgment in step S3 is marked as [S3]. In the following explanation of other steps, the notation of the steps in FIG. 2 is also indicated in FIG. 3 in a similar manner.

[0023] In step S4, the control device 60 judges whether the absolute value of the torque generated by the MG2 has become close to 0 Nm based on the information acquired by the MG2 state acquisition unit 60b. Specifically, the control device 60 judges whether the absolute value of the torque generated by the MG2 is greater than the absolute value of a second threshold value t2 set in advance. Here, the absolute values ​​are compared with each other in order to be applicable to both cases when the vehicle accelerates and decelerates, as shown in FIG. 3. The control device 60 judges whether the torque generated by the MG2 has become close to 0 Nm in order to predict whether the torque generated by the MG2 will subsequently reverse between positive torque and negative torque. When the control device 60 judges in step S4 as positive, the control device 60 proceeds to step S5. On the other hand, when the control device 60 judges in step S4 as negative, the control device 60 ends the process.

[0024] In step S5, the control device 60 determines whether the change in torque generated by MG2 is abrupt or not based on the information acquired by the MG2 state acquisition unit 60b. Specifically, the control device 60 determines whether the slope indicating the torque change is greater than a preset slope threshold. If the torque change is gradual, abnormal noise is unlikely to occur in the gear train 20. Therefore, such a case is excluded from the abnormal noise suppression measures. If the control device 60 determines yes in step S5, it proceeds to step S6. On the other hand, if the control device 60 determines no in step S5, it ends the process.

[0025] In step S6, the control device 60 determines whether the torque change in MG2 was a change from negative torque to positive torque based on the information acquired by the MG2 state acquisition unit 60b. This determination is made because the content of the control that the MG1 control unit 60a will subsequently execute varies depending on the content of the torque change. If the control device 60 determines in step S6 that the result is positive, the process proceeds to step S7. On the other hand, if the control device 60 determines in step S6 that the result is negative, the process proceeds to step S11.

[0026] The process proceeds to step S7 in the case of the acceleration side in FIG. 3. In step S7, the control device 60 determines whether or not there is an output request that requires engine start. Specifically, the control device 60 determines whether or not the required output is equal to or less than a threshold value te1 for starting the engine 14. When the engine 14 starts, noise suppression control is not performed. If the control device 60 makes a positive determination in step S7, the process proceeds to step S8. On the other hand, if the control device 60 makes a negative determination in step S7, the process ends.

[0027] In step S8, the MG1 control unit 60a causes MG1 to output positive torque. The positive torque of MG moves the gears included in the gear train 20 in the same direction as when the torque of MG2 changes from negative to positive. This causes the sun gear portion S1 to be in pre-contact with the case 19a at the contact point P1. After executing the process of step S8, the control device 60 proceeds to step S9.

[0028] In step S9, the control device 60 judges whether the torque change of the MG2 has become a sufficient positive torque based on the information acquired by the MG2 state acquisition unit 60b. Specifically, the control device 60 judges whether the value of the torque generated by the MG2 is greater than a third threshold value t3 for the positive torque set in advance. The third threshold value t3 is a value of the positive torque that will cause abnormal noise if no measures are taken. If no measures are taken, the sun gear part S1 moves due to the torque change and abnormal noise occurs. However, in this embodiment, the sun gear part S1 moves in advance by the MG1 generating positive torque. Therefore, the generation of abnormal noise is suppressed. If the control device 60 judges in step S9 as positive, the control device 60 proceeds to step S10. On the other hand, if the control device 60 judges in step S9 as negative, the control device 60 repeats the process of step S9 until the control device 60 judges in step S9 as positive.

[0029] In step S10, the MG1 control section 60a returns the MG1 torque to 0 Nm, thereby terminating the abnormal noise generation suppression control.

[0030] Meanwhile, in step S11, the MG1 control unit 60a causes MG1 to output negative torque. The negative torque of MG moves the gears included in the gear train 20 in the same direction as when the torque of MG2 changes from positive to negative. As a result, the gear train 20 is brought into a state where it is in advance in contact with another place at the contact points P2 and P3. After executing the process of step S11, the control device 60 proceeds to step S12.

[0031] In step S12, the control device 60 judges whether the torque change of the MG2 has become a sufficient negative torque based on the information acquired by the MG2 state acquisition unit 60b. Specifically, the control device 60 judges whether the value of the torque generated by the MG2 is greater than a third threshold value t3' for the negative torque set in advance. The third threshold value t3' is a value of the negative torque that will cause abnormal noise if no measures are taken. If no measures are taken, each gear in the gear train 20 moves due to the torque change, and abnormal noise is generated. However, in this embodiment, each gear moves in advance by the MG1 generating negative torque. Therefore, the generation of abnormal noise is suppressed. If the control device 60 judges in step S12 as positive, the control device 60 proceeds to step S10. On the other hand, if the control device 60 judges in step S12 as negative, the control device 60 repeats the process of step S12 until the control device 60 judges in step S12 as positive.

[0032] In step S10, the MG1 control section 60a returns the MG1 torque to 0 Nm, thereby ending the abnormal noise generation suppression control, as described above.

[0033] [effect] In the present embodiment, the control device 60 operates the MG1 when the torque of the MG2 exceeds 0 Nm while the engine 14 is stopped and the vehicle 10 is running due to the torque output by the MG2. By operating the MG1, the control device 60 moves the gear that moves when the torque of the MG2 exceeds 0 Nm in advance in the direction of movement of the gear. This makes it possible to suppress the generation of abnormal noise.

[0034] The above-described embodiments are merely examples for implementing the present invention, and the present invention is not limited to these. Various modifications of these embodiments are within the scope of the present invention. Furthermore, it is self-evident from the above description that various other embodiments are possible within the scope of the present invention. [Explanation of symbols]

[0035] 10 hybrid vehicle, 12 vehicle body, 14 engine, 19 power distribution mechanism, 19a case, 20 gear train, 22 counter drive gear, 24 output gear, 26 reduction gear, 28 counter driven gear, 30 drive pinion gear, 32 differential ring gear, 34 differential gear mechanism, 36 drive wheels, 60 control device, 60a MG1 control unit, 60b MG2 status acquisition unit, MG1 first rotating electric machine, MG2 second rotating electric machine.

Claims

[Claim 1] A control device for a hybrid vehicle in which an engine, a first rotating electric machine, and a second rotating electric machine are connected via a transmission mechanism, the speed change mechanism includes a gear whose movement direction is determined depending on whether the torque output by the second rotating electric machine is a torque change from positive torque to negative torque or a torque change from negative torque to positive torque, the hybrid vehicle is capable of running using torque output by the second rotating electric machine, The control device includes a first rotating electric machine control unit that, when the engine is stopped and the hybrid vehicle is driven by the torque output from the second rotating electric machine, operates the first rotating electric machine and executes control to move the gear in advance in a moving direction of the gear associated with the torque change of the second rotating electric machine when a torque change occurs between a state in which the second rotating electric machine outputs a positive torque and a state in which the second rotating electric machine outputs a negative torque. A control device for a hybrid vehicle.

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