Hybrid vehicle

Abstract

To more appropriately cope with a case where torque of a second motor crosses a value 0.SOLUTION: A hybrid vehicle is configured to: in the case that when torque of a second motor crosses a value 0, if an absolute value of a torque change rate, which is a change amount per unit time of the torque of the second motor, is equal to or greater than a predetermined change rate, execute pressing control to move axially a sun gear by torque of a first motor, which changes more slowly than the predetermined change rate, so as to press the sun gear against a wall portion before the torque of the second motor crosses the value 0; and if the absolute value of the torque change rate of the second motor is less than the predetermined change rate, not execute the pressing control.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to hybrid vehicles. [Background technology]

[0002] A hybrid vehicle has been proposed that includes an engine, a first motor, a second motor, and a planetary gear in which the first motor, engine, and second motor are connected to a sun gear, a carrier, and a ring gear (see, for example, Patent Document 1). In this hybrid vehicle, when the engine is operating while the vehicle is stopped, a pushing torque is applied by the second motor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication Summary of the Invention [Problem to be solved by the invention]

[0004] In a hybrid vehicle with such a hardware configuration, where the torque of the first motor and the torque of the second motor act on the sun gear in the axial direction of the planetary gear, causing the sun gear to move, it is considered that when the torque of the second motor crosses the value 0 (the sign is reversed), the first motor appropriately executes pressing control to suppress the gear rattle noise that occurs when the sun gear abuts on a wall. However, such pressing control is not always necessary, so a more appropriate response is required. The hybrid vehicle of the present disclosure has as its main objective a more appropriate response when the torque of the second motor crosses the value 0. [Means for solving the problem]

[0005] The hybrid vehicle of the present disclosure employs the following means to achieve the above-mentioned primary object: The hybrid vehicle of the present disclosure is a hybrid vehicle including an engine, a first motor, a second motor, a planetary gear including a sun gear connected to the first motor, a ring gear connected to the second motor, a plurality of pinion gears meshed with the sun gear and the ring gear, and a carrier supporting the plurality of pinion gears so as to be rotatable and revolvable and connected to the engine, and a control device, wherein the sun gear includes a wall portion provided at an interval in the axial direction of the planetary gear, and the sun gear, the ring gear, and the pinion gears are connected to a control device that controls the torque of the first motor and the The control device is configured as a helical gear in which an axial force of the planetary gear acts on the sun gear due to the torque of the second motor, and when the torque of the second motor crosses the value 0, if the absolute value of the torque change rate, which is the amount of change per unit time of the torque of the second motor, is equal to or greater than a predetermined change rate, the control device executes a pressing control to move the sun gear in the axial direction and press it against the wall portion using the torque of the first motor, which changes more slowly than the predetermined change rate, before the torque of the second motor crosses the value 0, and if the absolute value of the torque change rate of the second motor is less than the predetermined change rate, the control device does not execute the pressing control.

[0006] In the hybrid vehicle of the present disclosure, the above-described control can suppress rattle noise caused by contact between the sun gear and a wall when the absolute value of the torque change rate of the second motor is equal to or greater than a predetermined rate, and can suppress changes in the engine crank angle to prevent subsequent deterioration of engine startability when the absolute value of the torque change rate of the second motor is less than the predetermined rate, thereby more appropriately dealing with the torque of the second motor crossing the zero value. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a schematic configuration diagram of a hybrid vehicle 20 according to an embodiment of the present disclosure. [Figure 2] 10 is a flowchart illustrating an example of a processing routine. [Figure 3]10 is an explanatory diagram showing a state in which the torque Tm2 of the motor MG2 crosses the value 0 and transitions from negative to positive. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0008] An embodiment of the present disclosure will be described with reference to the drawings. Fig. 1 is a schematic diagram of a hybrid vehicle 20 according to an embodiment of the present disclosure. As shown in the figure, the hybrid vehicle 20 according to the embodiment includes an engine 22, motors MG1 and MG2, inverters 25 and 26, a battery 28, a planetary gear 30, a gear mechanism 31, and a hybrid vehicle electronic control unit (HVECU) 70.

[0009] The engine 22 is configured as an internal combustion engine that outputs power using gasoline, diesel, or the like as fuel. The motors MG1 and MG2 are configured as, for example, synchronous generator motors, and are rotationally driven by switching on and off a plurality of switching elements of the inverters 25 and 26. The battery 28 is configured as, for example, a lithium-ion secondary battery or a nickel-metal hydride secondary battery, and is connected to the inverters 25 and 26 via a power line 29.

[0010] The planetary gear 30 is configured as a single-pinion planetary gear mechanism and includes a sun gear 30s, a ring gear 30r formed on the inner circumferential surface of a rotating member 30o, a plurality of pinion gears 30p meshing with the sun gear 30s and the ring gear 30r, respectively, and a carrier 30c that supports the plurality of pinion gears 30p so that they can rotate and revolve. A rotor of a motor MG1 is connected to the sun gear 30s, and a crankshaft 23 of the engine 22 is connected to the carrier 30c. The sun gear 30s is disposed between a left side wall 41 and a right side wall 42 in the axial direction of the planetary gear 30 (the left-right direction in FIG. 1).

[0011] The gear mechanism 31 includes a counter drive gear 32 formed on the outer peripheral surface of the rotating member 30o, a reduction gear 33 fixed to the rotor of the motor MG2, a counter driven gear 35 fixed to a counter shaft 34 and meshing with the counter drive gear 32 and the reduction gear 33, a drive pinion gear (final drive gear) 36 fixed to the counter shaft 34, and a differential ring gear 37 meshing with the drive pinion gear 36 and connected to the drive wheels DW via an axle DS and a differential gear (not shown). The rotor of the motor MG2 is connected to the ring gear 30r via the reduction gear 33, the counter driven gear 35, and the counter drive gear 32.

[0012] In this embodiment, the sun gear 30s, the ring gear 30r, and the pinion gears 30p are configured as helical gears, and a force in the axial direction of the planetary gear 30 acts on the sun gear 30s due to the torque of the motor MG1 and the torque of the motor MG2. Specifically, when the torque of the motor MG1 is positive or negative, a force acts on the sun gear 30s toward the right side wall 42 (to the right in FIG. 1 ) and the left side wall 41 (to the left in FIG. 1 ), respectively. When the torque of the motor MG2 is positive or negative, a force acts on the left side wall 41 and the right side wall 42, respectively. Note that the positive and negative torque of the motor MG1 is a torque that increases or decreases the rotation speed of the engine 22, respectively, and the positive and negative torque of the motor MG2 is a torque that increases or decreases the vehicle speed during forward travel, respectively. FIG. 1 illustrates a case in which the sun gear 31 abuts against the right side wall 42.

[0013] The HVECU 70 includes a microcomputer. The HVECU 70 receives inputs of the crank angle θcr of the crankshaft of the engine 22 from a crank position sensor, the rotational positions θm1 and θm2 of the rotors of the motors MG1 and MG2 from a rotational position sensor, the phase currents Iu1, Iv1, Iw1, Iu2, Iv2, and Iw2 of the motors MG1 and MG2 from current sensors, and the voltage Vb and current Ib of the battery 28 from voltage and current sensors. The HVECU 70 also receives inputs of an ignition signal from an ignition switch 80, the operating position (shift position SP) of a shift lever 81 from a shift position sensor 82, the depression amount (accelerator opening Acc) of an accelerator pedal 83 from an accelerator pedal position sensor 84, the depression amount (brake pedal position BP) of a brake pedal 85 from a brake pedal position sensor 86, and the vehicle speed V from a vehicle speed sensor 87. The HVECU 70 outputs control signals to the engine 22 and the inverters 25 and 26. The HVECU 70 calculates the rotation speed Ne of the engine 22 based on the crank angle θcr of the engine 22, calculates the electrical angles θe1, θe2 and rotation speeds Nm1, Nm2 of the motors MG1, MG2 based on the rotational positions θm1, θm2 of the rotors of the motors MG1, MG2, calculates the d-axis and q-axis currents Id1, Iq1, Id2, Iq2 of the motors MG1, MG2 based on the phase currents Iu1, Iv1, Iw1, Iu2, Iv2, Iw2 and the electrical angles θe1, θe2 of the motors MG1, MG2, and calculates the torques Tm1, Tm2 of the motors MG1, MG2 based on the d-axis and q-axis currents Id1, Iq1, Id2, Iq2.

[0014] The hybrid vehicle 20 of the embodiment performs hybrid running (HV running) in which the vehicle runs with the engine 22 operating, and electric running (EV running) in which the vehicle runs with the engine 22 stopped. In HV running or EV running, the engine 22 and the motors MG1 and MG2 (inverters 25 and 26) are basically controlled as follows.

[0015] During HV driving, the HVECU 70 sets a driving torque Td* required for driving based on the accelerator pedal position Acc and the vehicle speed V, sets a required power Pe* for the engine 22 based on the driving power Pd*, the vehicle speed V, and the power storage percentage SOC of the battery 28, and sets a target rotation speed Ne* and target torque Te* for the engine 22 and torque commands Tm1* and Tm2* for the motors MG1 and MG2 so that the required power Pe* is output from the engine 22 and the vehicle drives using the driving torque Td*. The HVECU 70 then controls the engine 22 so that the engine 22 operates based on the target rotation speed Ne* and the target torque Te*, and controls the inverters 41 and 42 so that the motors MG1 and MG2 are driven by the torque command Tm2*. If a stop condition is met during HV driving, such as when the required power Pe* falls below the threshold Peref, the HVECU 70 stops the engine 22 and switches to EV driving.

[0016] In EV driving, the HVECU 70 sets the driving torque Td* in the same way as in HV driving, sets the torque command Tm1* of the motor MG1 to a value of 0, sets the torque command Tm2* of the motor MG2 so that driving is performed using the driving torque Td*, and controls the inverters 41, 42 so that the motors MG1, MG2 are driven by the torque command Tm2*. During EV driving, when a start condition is met, such as when the required power Pe* calculated in the same way as in HV driving reaches or exceeds a threshold value Peref, the engine 22 is started and the vehicle transitions to HV driving. The engine 22 is started by the motor MG1 cranking the engine 22 based on the crank angle θcr and the rotation speed Ne of the engine 22, and when the rotation speed Ne of the engine 22 reaches or exceeds a threshold value Neref, control of the engine 22 is initiated.

[0017] Next, the operation of the hybrid vehicle 20, particularly the operation when the torque Tm2 of the motor MG2 crosses over the value 0, will be described. In this embodiment, the time when the torque Tm2 of the motor MG2 crosses over the value 0 is defined as a period from when a prediction that the torque Tm2 will cross over the value 0 is started based on the torque command Tm2*, based on the fact that the torque Tm2 of the motor MG2 follows the torque command Tm2*, until a predetermined time has elapsed since the torque Tm2 crossed over the value 0. FIG. 2 is a flowchart showing an example of a processing routine repeatedly executed by the HVECU 70.

[0018] 2 is executed, the HVECU 70 first determines whether the vehicle is in EV driving mode (step S100) and whether the torque Tm2 of the motor MG2 is about to cross the value 0 (step S110). If it is determined that the vehicle is not in EV driving mode or that the torque Tm2 of the motor MG2 is not about to cross the value 0, the HVECU 70 ends this routine.

[0019] When it is determined that the vehicle is in EV driving mode and that the torque Tm2 of the motor MG2 is about to cross the value 0, it is determined whether the torque Tm2 of the motor MG2 will cross the value 0 and transition from positive to negative (step S120). This process is a process for determining whether the sun gear 30s will transition from contact with the left side wall portion 41 to contact with the right side wall portion 42 as the torque Tm2 of the motor MG2 crosses the value 0.

[0020] If it is determined in step S120 that the torque Tm2 of the motor MG2 crosses the value 0 and transitions from positive to negative, the routine determines whether the absolute value of the torque change rate ΔTm2, which is the amount of change per unit time of the torque Tm2 of the motor MG2, is equal to or greater than a threshold value ΔTm2ref (step S130). If it is determined that the absolute value of the torque change rate ΔTm2 of the motor MG2 is equal to or greater than the threshold value ΔTm2ref, the routine executes positive-side pressing control of the motor MG1 (step S140), and ends this routine. In the positive-side pressing control of the motor MG1, before the torque Tm2 of the motor MG2 crosses the value 0, the motor MG1 is caused to output a torque whose absolute value increases more slowly than the threshold value ΔTm2ref from the value 0 toward a first predetermined positive torque. When the torque Tm2 of the motor MG2 crosses the value 0 and transitions from positive to negative at a relatively large torque change rate ΔTm2, a relatively loud rattle noise may occur when the sun gear 30s abuts against the right side wall portion 42. In this embodiment, by executing the positive side pressing control of the motor MG1, the sun gear 30s can be gently brought into contact with the right side wall portion 42 before the torque Tm2 of the motor MG2 crosses the value 0, thereby suppressing gear rattle noise.

[0021] If it is determined in step S130 that the absolute value of the torque change rate ΔTm2 of the motor MG2 is less than the threshold value ΔTm2ref, the routine ends without executing the positive side pressing control of the motor MG1. In this case, it is assumed that the rattle noise generated when the sun gear 30s abuts against the right side wall portion 42 when the torque Tm2 of the motor MG2 crosses the value 0 and transitions from positive to negative is small. For this reason, the positive side pressing control of the motor MG1 is not executed. This suppresses the change in the crank angle θcr of the engine 22, thereby suppressing a subsequent deterioration in the startability of the engine 22.

[0022] If it is determined in step S120 that the torque Tm2 of the motor MG2 crosses the value 0 and transitions from negative to positive, it is determined whether the absolute value of the torque change rate ΔTm2 of the motor MG2 is equal to or greater than a threshold value ΔTm2ref (step S150). The threshold value ΔTm2ref may be, for example, the same value as the threshold value ΔTm2ref. If it is determined that the absolute value of the torque change rate ΔTm2 of the motor MG2 is equal to or greater than the threshold value ΔTm2ref, negative side push-up control of the motor MG1 is executed (step S160), and this routine ends. In the negative side push-up control of the motor MG1, before the torque Tm2 of the motor MG2 crosses the value 0, the motor MG1 is caused to output a torque whose absolute value increases more slowly than the threshold value ΔTm2ref from the value 0 toward a second predetermined negative torque. When the torque Tm2 of the motor MG2 crosses the value 0 and transitions from negative to positive at a relatively large torque change rate ΔTm2, a relatively large gear rattle noise may occur when the sun gear 30s contacts the left side wall portion 41. In the embodiment, by executing negative side pressing control of the motor MG1, the sun gear 30s can be gently brought into contact with the left side wall portion 41 before the torque Tm2 of the motor MG2 crosses the value 0, thereby suppressing the gear rattle noise.

[0023] If it is determined in step S150 that the absolute value of the torque change rate ΔTm2 of the motor MG2 is less than the threshold value ΔTm2ref, the routine ends without executing the negative side pressing control of the motor MG1. In this case, it is assumed that the rattle noise generated when the sun gear 30s abuts against the left side wall portion 41 as the torque Tm2 of the motor MG2 crosses the value 0 and transitions from negative to positive is small. For this reason, the negative side pressing control of the motor MG1 is not executed. This suppresses changes in the crank angle θcr of the engine 22, thereby suppressing subsequent deterioration in the startability of the engine 22.

[0024] FIG. 3 is an explanatory diagram showing the state when the torque Tm2 of motor MG2 crosses the value 0 and transitions from negative to positive. FIG. 3 illustrates the torque Tm2 of motor MG2, the torque Tm1 of motor MG1, and the position of the sun gear 30s when the absolute value of the torque change rate ΔTm2 is equal to or greater than the threshold value ΔTm2ref. The position of the sun gear 30s is illustrated by a dashed line in a comparative example in which the negative side press-fit control of motor MG1 is not executed. As shown in the figure, by executing the negative side press-fit control of motor MG1, the sun gear 30s can be brought into gentle contact with the left side wall portion 41 before the torque Tm2 of motor MG2 crosses the value 0, thereby suppressing gear rattle noise, compared to the comparative example in which the negative side press-fit control is not executed. In addition, when the absolute value of the torque change rate ΔTm2 is less than the threshold value ΔTm2ref, even if negative side pressing control of motor MG1 is not performed, it is expected that the gear rattle noise when the sun gear 30s contacts the left side wall portion 41 as the torque Tm2 of motor MG2 crosses the value 0 will be small.

[0025] In the hybrid vehicle 20 according to the embodiment described above, when the torque Tm2 of the motor MG2 crosses the value 0, if the absolute value of the torque change rate ΔTm2 of the motor MG2 is equal to or greater than the threshold value ΔTm2ref, the positive side push-up control or the negative side push-up control is executed. However, if the absolute value of the torque change rate ΔTm2 of the motor MG2 is less than the threshold value ΔTm2ref, the positive side push-up control or the negative side push-up control is not executed. As a result, in the former case, gear rattle can be suppressed, and in the latter case, subsequent deterioration in the startability of the engine 22 can be suppressed. In other words, a more appropriate response can be made when the torque Tm2 of the motor MG2 crosses the value 0. Specifically, it is possible to achieve both suppression of gear rattle and subsequent deterioration in the startability of the engine 22.

[0026] The above describes the forms for implementing the present disclosure using embodiments, but the present disclosure is not limited to these embodiments in any way, and it goes without saying that the present disclosure can be implemented in various forms within the scope that does not deviate from the gist of the present disclosure. [Industrial Applicability]

[0027] The present disclosure is applicable to the hybrid vehicle manufacturing industry and the like. [Explanation of symbols]

[0028] 20 Hybrid vehicle, 22 Engine, 30 Planetary gear, 41, 42 Wall, 70 Hybrid vehicle, MG1, MG2 Motor.

Claims

[Claim 1] A hybrid vehicle comprising: an engine; a first motor; a second motor; a planetary gear including a sun gear connected to the first motor, a ring gear connected to the second motor, a plurality of pinion gears meshing with the sun gear and the ring gear, respectively, and a carrier supporting the plurality of pinion gears so as to be rotatable and revolvable and connected to the engine; and a control device, a wall portion provided at a distance from the sun gear in the axial direction of the planetary gear; the sun gear, the ring gear, and the pinion gear are configured as helical gears in which a force in the axial direction of the planetary gear acts on the sun gear due to the torque of the first motor and the torque of the second motor, When the torque of the second motor crosses over the value 0, if an absolute value of a torque change rate, which is a change amount per unit time of the torque of the second motor, is equal to or greater than a predetermined change rate, the control device executes a pressing control to move the sun gear in the axial direction by the torque of the first motor, which changes more slowly than the predetermined change rate, and press the sun gear against the wall portion before the torque of the second motor crosses over the value 0, and does not execute the pressing control if the absolute value of the torque change rate of the second motor is less than the predetermined change rate. Hybrid car.

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