Vehicle control method

Abstract

To improve gas mileage while performing damping control of a vehicle.SOLUTION: Damper torque is a hybrid vehicle control method in which damping control to remove vibration by applying opposite phase torque to a motor is performed. Whether a difference between engine torque with which predetermined vibration occurs when the damping control is performed during rotation of an engine at the predetermined speed and engine torque with which predetermine vibration occurs when the damping control is not performed is a predetermined value or more, and when the difference is the predetermined value or more, the damping control is performed.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a method for controlling a vehicle.

Background Art

[0002] In recent years, an internal combustion engine and a motor have been used as power sources for vehicles, and a hybrid vehicle that uses both an internal combustion engine and a motor as power sources is known.

[0003] When the vehicle is running, vehicle enclosure noise may occur. Specifically, since the vehicle is composed of elastic bodies, torsional vibration occurs when components and the systems to which they are coupled are subjected to temporally varying torques. When the vibration frequency of the torque matches the torsional resonance frequency, the amplitude of the torsional vibration increases, causing noise and the like.

[0004] In Patent Document 1, as a technique for reducing this torsional vibration, control is disclosed in which torque fluctuations are reduced by outputting, in reverse phase, the damper torque calculated from the crank angle and the input shaft angle by a motor.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the control method disclosed in Patent Document 1, since it is necessary to output torque from the motor, when the vehicle does not require vibration control, if torque for vibration control continues to be output, there is a problem that fuel efficiency decreases.

[0007] The present disclosure has been made in view of the problems described above, and provides a vehicle control method that improves fuel efficiency by performing vibration damping control only when vibration damping control is required for the vehicle.

Means for Solving the Problems

[0008] The vehicle control method according to the present disclosure is a control method for a hybrid vehicle that performs vibration damping control to remove vibration by applying torque of a phase opposite to the damper torque to a motor. When rotating the engine at a predetermined rotational speed, it is determined whether or not the difference between the engine torque at which predetermined vibration occurs when vibration damping control is performed and the engine torque at which predetermined vibration occurs when vibration damping control is not performed is equal to or greater than a predetermined value. When the difference is equal to or greater than the predetermined value, vibration damping control is executed. Thereby, it is possible to determine whether or not to execute vibration damping control according to the difference between the engine torque at which vibration occurs when vibration damping control is performed and the engine torque at which vibration occurs when vibration damping control is not performed.

[0009] Furthermore, the vehicle control method according to the present disclosure sets, as a region where vibration damping control is to be executed, a region where the rotational speed of the engine is such that the difference between the engine torque at which predetermined vibration occurs when vibration damping control is performed and the engine torque at which predetermined vibration occurs when vibration damping control is not performed is equal to or greater than a predetermined torque, and the engine torque is equal to or less than the engine torque at which predetermined vibration occurs when vibration damping control is performed and equal to or greater than the engine torque at which predetermined vibration occurs when vibration damping control is not performed. In the region where vibration damping control is to be executed, the battery output required for vibration damping control is calculated using the rotational speed of the engine and the value of the vibration damping torque generated when performing vibration damping, and before performing the vibration damping control, the calculated battery output required for vibration damping control is reserved. Thereby, when vibration damping control is required, vibration damping control is more likely to be executed.

[0010] Furthermore, when the battery output required for the vibration control cannot be reserved, the vehicle control method according to the present disclosure increases the engine speed until the condition for not executing the vibration control is satisfied. Thereby, when the battery output cannot be secured, it is possible to perform vibration control without relying on the battery output.

Effects of the Invention

[0011] Thereby, it is possible to improve the fuel efficiency while executing the vibration control of the vehicle.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Modes for Carrying Out the Invention

[0013] Embodiment 1 Hereinafter, with reference to the drawings, a vehicle control method according to Embodiment 1 will be described. Here, the vehicle is described as a hybrid vehicle. FIG. 1 is a diagram showing an example of the connection related to the power of the vehicle.

[0014] The vehicle 1 includes an internal combustion engine (hereinafter referred to as an engine) 11, a motor 12, a conversion unit 13, and wheels 14. The vehicle 1 also includes a damper 21 that connects between the engine 11 and the motor 12, an input shaft 22 that connects between the motor 12 and the conversion unit 13, and a drive shaft 23 that connects between the conversion unit 13 and the wheels 14.

[0015] Also, as shown in FIG. 2, the vehicle 1 has a configuration related to the operation control of the vehicle. Specifically, when performing vibration damping control and when not performing vibration damping control, the vehicle 1 includes a storage unit 31 that stores information such as the upper limit of NV (Noise Vibration) performance, a calculation unit 32, a determination unit 33 that determines whether to perform vibration damping control, and a control unit 34 that causes the motor 12 to execute vibration damping control according to the determination of the determination unit 33.

[0016] The engine 11 is typically a gasoline engine, and repeatedly performs a process of compressing a mixture of gasoline as fuel and air, then igniting, burning, and expanding, outputs kinetic energy, and generates torque.

[0017] The motor 12 generates torque using electric power stored in a battery stored in the vehicle 1. The motor 12 generates a vibration damping torque that is out of phase with the damper torque applied from the engine 11 to the damper 21 according to the control from the control unit 34. That is, the vibration damping torque is a torque generated to perform vibration damping.

[0018] Here, the electric power of the battery is used to generate power for rotating the wheels 14 by the motor 12, to cause the motor 12 to execute vibration damping control, and to operate electrical devices in the vehicle.

[0019] The conversion unit 13 performs force conversion on the power input from the engine 11 or the motor 12, which is the power source, via the input shaft 22 so that the wheels 14 operate appropriately according to the driving state of the vehicle 1.

[0020] Typically, the conversion unit 13 includes a transmission and a differential gear. The transmission consists of gears, shafts, etc., and transmits the power of the power source to the shaft by changing the torque, rotational speed, and rotational direction of the power. The differential gear is a differential device that converts to absorb the rotational difference between the left and right wheels according to road conditions and driving conditions such as when the vehicle 1 turns a curve.

[0021] The wheels 14 perform a rotational operation by receiving the force converted by the conversion unit 13 via the drive shaft 23. Thereby, the vehicle 1 travels.

[0022] The storage unit 31 stores the NV (Noise Vibration) performance in the case of having vibration control and in the case of not having vibration control. For example, the storage unit 31 stores the content shown in FIG. 3.

[0023] Here, FIG. 3 shows a with-vibration NV line indicating a state in which, for a predetermined gear stage in the vehicle 1, when the engine speed is changed with vibration control always being present, the value of the engine torque that is the upper limit in terms of NV performance changes, a without-vibration NV line indicating a state in which, when the engine speed is changed with vibration control always being absent, the value of the engine torque that is the upper limit in terms of NV performance changes, and an NV line indicating the NV performance allowed in this vehicle 1.

[0024] That is, each NV line shown in FIG. 3 is a line indicating the value of the upper limit of the engine torque allowed for each engine speed based on the fact that when a large engine torque is generated with respect to a predetermined engine speed, the NV performance deteriorates, and when the engine torque is reduced, the NV performance improves.

[0025] Furthermore, Fig. 3 shows a vibration suppression ON line, which is a criterion for determining whether to execute vibration suppression control in the motor 12. In the following, the state in which vibration suppression control is performed may be described as the state where vibration suppression control is ON, and the state in which vibration suppression control is not performed may be described as the state where vibration suppression control is OFF. The vibration suppression ON line will be described in detail later.

[0026] The arithmetic unit 32 can perform an arithmetic operation for converting information so that the determination unit 33 can execute a determination based on the information stored in the storage unit 31, for example.

[0027] The determination unit 33 determines whether to perform vibration suppression control on the motor 12. Specifically, in Fig. 3, when the difference between the NV line in the case of having vibration suppression control and the NV line in the case of not having vibration suppression control is greater than a predetermined value, the determination unit 33 determines to execute vibration suppression control. That is, in Fig. 3, at the location where these two lines are widely separated vertically, the determination unit 33 determines to execute vibration suppression control.

[0028] On the other hand, when the difference between the NV line in the case of having vibration suppression control and the NV line in the case of not having vibration suppression control is less than or equal to a predetermined value, the determination unit 33 determines not to execute vibration suppression control.

[0029] That is, the determination unit 33 determines whether the difference between the engine torque that generates a predetermined vibration when vibration suppression control is performed and the engine torque that generates a predetermined vibration when vibration suppression control is not performed is greater than or equal to a predetermined value when the engine is rotated at a predetermined rotational speed. Here, the predetermined vibration is the upper limit of the vibration that can be tolerated in the vehicle 1. Also, the predetermined value can be an arbitrary value, but typically, it is the value of the upper limit of the vibration suppression torque described later.

[0030] The control unit 34 controls the motor 12 to change the implementation state of the vibration control according to the determination result of the determination unit 33. Here, the control unit 34 determines whether the difference between the engine torque at which a predetermined vibration occurs when the vibration control is performed by the determination unit 33 and the engine torque at which a predetermined vibration occurs when the vibration control is not performed is equal to or greater than a predetermined value, and executes the vibration control with at least one of the conditions.

[0031] As will be described later, the control unit 34 can also control the battery output for operating the motor 12 and the power for operating other power systems.

[0032] Hereinafter, it is described on the assumption that the vehicle 1 has sensors capable of acquiring the engine speed and engine torque values, and appropriately acquires these sensor values.

[0033] Here, an example of the procedure of the vibration control in the vehicle 1 will be described with reference to the flowchart shown in FIG. 4.

[0034] The upper limit of the vibration control torque generated from the motor 12 for vibration control is set to a value that does not significantly affect the performance such as vehicle power by generating the vibration control torque. For example, the upper limit of the vibration control torque is defined as 30 Nm.

[0035] The determination unit 33 determines whether the currently acquired engine speed and engine torque of the vehicle 1 are equal to or higher than the vibration control ON line on the two-dimensional graph shown in FIG. 3 (step S11). Here, the determination in the determination unit 33 will be described by explaining FIG. 3 in more detail.

[0036] As shown in FIG. 3, in the NV line with vibration damping, when the rotational speed of a predetermined engine increases from a state lower than the rotational speed R1 to the rotational speed R1, the value of the engine torque increases as the rotational speed increases. Then, when the rotational speed of the engine is increased from the rotational speed R1 to the rotational speed R3, the value of the engine torque is in a substantially constant state in the NV line with vibration damping. And when the rotational speed is further increased and the rotational speed of the engine is higher than the rotational speed R3, the value of the engine torque also increases as the rotational speed increases.

[0037] On the other hand, in the NV line without vibration damping, when the rotational speed of a predetermined engine increases from a state lower than the rotational speed R1 to the rotational speed R2, the value of the engine torque increases as the rotational speed increases. Note that this rotational speed R2 is higher than the rotational speed R1. At this time, when the rotational speed of the engine is increased from the rotational speed R1 to the rotational speed R4, the value of the engine torque is in a substantially constant state in the NV line without vibration damping. This rotational speed R4 is slightly higher than the rotational speed R3. And when the rotational speed is further increased and the rotational speed of the engine is higher than the rotational speed R4, the value of the engine torque also increases as the rotational speed increases.

[0038] Here, regarding the NV line with vibration damping and the NV line without vibration damping in FIG. 3, the difference in the value of the engine torque when it is the rotational speed of the engine will be described. As shown in FIG. 3, the NV line with vibration damping is always above the NV line without vibration damping. That is, if there is vibration damping, the upper limit of the engine torque in terms of allowable NV performance is higher when there is vibration damping than when there is no vibration damping at the same rotational speed.

[0039] From a state where the rotational speed is lower than the rotational speed R1 to the rotational speed R1, in the NV line with vibration damping, the value of the engine torque increases as the rotational speed of the engine increases. Also, similarly in the NV line without vibration damping, the value of the engine torque increases as the rotational speed of the engine increases. Here, as shown in FIG. 3, in this section, the NV line with vibration damping and the NV line without vibration damping are substantially parallel.

[0040] In the range up to this rotational speed R1, the NV line with vibration damping and the NV line without vibration damping deviate significantly. In other words, at the same engine rotational speed, the difference in the upper limit of the engine torque in terms of the allowable NV performance between the case with vibration damping and the case without vibration damping is large.

[0041] From rotational speed R1 to rotational speed R2, for the NV line with vibration damping, the value of the engine torque remains almost constant even as the engine rotational speed increases. For the NV line without vibration damping, the value of the engine torque increases as the engine rotational speed increases. In other words, from rotational speed R1 to rotational speed R2, the allowable engine torque is almost constant in the case with vibration damping, but the allowable engine torque increases as the rotational speed increases in the case without vibration damping. That is, in this range from rotational speed R1 to rotational speed R2, the NV line without vibration damping gradually approaches the NV line with vibration damping as the rotational speed increases.

[0042] From rotational speed R2 to rotational speed R3, for the NV line with vibration damping, the value of the engine torque is almost constant. On the other hand, for the NV line without vibration damping as well, the value of the engine torque is almost constant. That is, in this range from rotational speed R2 to rotational speed R3, the allowable engine torque is almost constant regardless of whether there is vibration damping or not, independent of the rotational speed. At this time, the NV line with vibration damping and the NV line without vibration damping are almost parallel and close to each other.

[0043] From rotational speed R3 to rotational speed R4, for the NV line with vibration damping, the value of the engine torque increases as the engine rotational speed increases. For the NV line without vibration damping, the value of the engine torque remains almost constant even as the engine rotational speed increases. Here, since the difference in rotational speed between rotational speed R3 and rotational speed R4 is small, the NV line with vibration damping and the NV line without vibration damping remain close to each other even as the rotational speed increases.

[0044] When the rotational speed is higher than the rotational speed R4, in the case of the NV line with vibration control and the NV line without vibration control, as the rotational speed of the engine increases, the value of the engine torque increases. As shown in FIG. 3 here, in this section, the NV line with vibration control and the NV line without vibration control are substantially parallel, and the NV line with vibration control and the NV line without vibration control remain in a state of being close to each other.

[0045] Next, the NV line of the vehicle, which is the upper limit line in terms of the NV performance of the vehicle, will be described. As shown in FIG. 3, when the rotational speed of the engine is lower than the rotational speed R2, the NV line is set slightly above the NV line with vibration control. When the rotational speed of the engine is R2 or higher, the NV line is set slightly above the NV line without vibration control.

[0046] At this time, the region where the rotational speed of the engine is lower than the rotational speed R2 is the region where the NV line of the vehicle is above the NV line with vibration control and the NV line without vibration control. That is, this region is the region where the NV line is above the vibration control torque upper limit.

[0047] On the other hand, in the region where the rotational speed of the engine is R2 or higher, the NV line of the vehicle is higher than the NV line without vibration control but lower than the NV line with vibration control. That is, this region is the region where the NV line of the vehicle is below the vibration control torque upper limit.

[0048] Here, as shown in FIG. 3, the vibration control ON line for determining whether to turn on the vibration control is set as follows. In vehicle 1, when the rotational speed and engine torque output of the engine shown in FIG. 3 are equal to or higher than the vibration control ON line, vibration control will be performed.

[0049] More specifically, the vibration control ON line is set slightly below the NV line without vibration control in the region where the rotational speed of the engine is lower than the rotational speed R2. This region where the rotational speed of the engine is lower than the rotational speed R2 is, that is, the region where the deviation between the NV line with vibration control and the NV line without vibration control is large.

[0050] Also, as shown in FIG. 3, in a state where the engine speed is equal to or higher than the speed R2, the vibration control ON line is set infinitely upward. In other words, in a state where the engine speed is equal to or higher than the speed R2, regardless of the values of the engine speed and engine torque, it is set to be determined that it is below the vibration control ON line.

[0051] Here, when the determination unit 33 determines that the engine speed and engine torque of the vehicle are equal to or higher than the vibration control ON line in FIG. 3 (Yes in step S11), it executes vibration control (step S12). That is, the control unit 34 turns on the vibration control in the motor 12.

[0052] On the other hand, when the determination unit 33 determines that the engine speed and engine torque of the vehicle are lower than the vibration control ON line in FIG. 3 (No in step S11), it does not execute vibration control (step S13). That is, the control unit 34 turns off the vibration control in the motor 12.

[0053] Thereby, in a range where the NV performance of the vehicle can be satisfied without vibration control, the vibration control can be turned off.

[0054] On the other hand, in a range where the NV performance of the vehicle cannot be satisfied without vibration control and can be satisfied by providing vibration control, the vibration control can be turned on. Specifically, in the vehicle 1, in a range where the difference between the NV lines with and without vibration control is equal to or higher than the vibration torque upper limit, that is, in a region where the above-described engine speed is lower than the speed R2, when the engine torque exceeds the NV line without vibration control, the vibration control can be turned on.

[0055] Therefore, in vehicle 1, a vibration suppression ON line is set on a two-dimensional graph showing the relationship between the engine speed and the engine torque, and vibration suppression control can be executed when the engine torque is equal to or greater than the value of the vibration suppression ON line. At this time, in vehicle 1, when the difference between the NV line with vibration suppression and the NV line without vibration suppression is large, it is more advantageous for energy management to raise the NV line with vibration suppression. Therefore, the efficiency can be improved by executing the vibration suppression control.

[0056] On the other hand, in vehicle 1, when the difference between the NV line with vibration suppression and the NV line without vibration suppression is small and the difference is less than 30 Nm, which is the upper limit of the vibration suppression torque, it is considered more advantageous for energy management not to perform the huddled vibration suppression. Therefore, it is possible to control not to execute the vibration suppression control. Thereby, in vehicle 1, the power of the battery used for the vibration suppression control can be used efficiently.

[0057] Embodiment 2 In Embodiment 1, it was described that vibration suppression is performed by outputting a torque of opposite phase to the damper torque by a motor. However, since it is necessary to output torque from the motor, if the output is taken away by other controls or if the torque cannot be generated by the motor, it is considered that the NV performance of the vehicle may deteriorate.

[0058] Therefore, in the region where the vibration suppression control is executed, a method for suppressing the deterioration of the NV performance of the vehicle by reserving the necessary battery output for generating the torque of the vibration suppression control by the motor and calculating the upper limit of the system torque that can be used for power and the like will be described.

[0059] In addition, in Embodiment 2, since a vehicle having the same configuration as the vehicle 1 described in Embodiment 1 is used, the same reference numerals are given to each component article, and the description thereof is omitted.

[0060] Here, with reference to FIG. 5, an example of a procedure for determining whether vibration suppression control is necessary and reserving the battery output for the vibration suppression control when the vibration suppression control is necessary will be described.

[0061] The determination unit 33 determines whether the rotational speed of the engine of the current vehicle 1 and the engine torque are within the vibration damping region (step S21).

[0062] Here, the vibration damping region will be described. FIG. 6 shows a vibration damping NV line indicating a state in which the value of the engine torque that is the upper limit in terms of NV performance changes when the rotational speed of the engine is changed with vibration damping control always being in effect, a vibration damping-free NV line indicating a state in which the value of the engine torque that is the upper limit in terms of NV performance changes when the rotational speed of the engine is changed with vibration damping control always being not in effect, an NV line allowed for this vehicle 1, and a set vibration damping region. Here, since the vibration damping NV line, the vibration damping-free NV line, the NV line, and the vibration damping ON line are the same as those shown in FIG. 3, the description thereof is omitted.

[0063] The vibration damping region shown in FIG. 6 is a region where the rotational speed of the engine is lower than the rotational speed R2, and is a region sandwiched between the vibration damping NV line above and the vibration damping-free NV line below.

[0064] In other words, the vibration damping region is a region of the rotational speed of the engine where the difference between the engine torque at which a predetermined vibration occurs when vibration damping control is implemented and the engine torque at which a predetermined vibration occurs when vibration damping control is not implemented is equal to or greater than a predetermined value. That is, the range of the horizontal axis set as the vibration damping region in FIG. 6 is a range where the difference between the vibration damping NV line and the vibration damping-free NV line on the vertical axis is large, and here it is a range lower than the rotational speed R2.

[0065] Furthermore, the vibration damping region is a region of the engine torque that is equal to or less than the engine torque at which a predetermined vibration occurs when vibration damping control is implemented and equal to or greater than the engine torque at which a predetermined vibration occurs when vibration damping control is not implemented. That is, the range of the vertical axis set as the vibration damping region in FIG. 6 has the vibration damping NV line as the upper limit and the vibration damping-free NV line as the lower limit.

[0066] If the engine speed of the vehicle 1 and the engine torque are within the vibration damping region (Yes in step S21), the vehicle 1 calculates the battery output reserved for performing the stuffy vibration damping control by the motor 12 (step S22).

[0067] Here, the calculation unit 32 calculates the magnitude of the reserved battery output by using the engine speed and the upper limit value of the vibration damping torque generated when performing vibration damping. More specifically, the calculation unit 32 calculates the value of the battery output for generating the torque for vibration damping control by the motor 12 from the engine speed and the engine torque being within the vibration damping region and the upper limit value of the vibration damping torque.

[0068] Here, FIG. 7 is a diagram showing an image of the battery output reserve. As shown in FIG. 7, the output of the battery required to execute the vibration damping control by the motor becomes a sine wave shape that repeatedly increases alternately between the Win side and the Wout side over time. Therefore, in step S22, as shown in FIG. 7, the value of the reserved battery output is calculated so as to cover the magnitudes of both of these amplitudes on both the Win side and the Wout side of the battery. Then, it proceeds to step S23.

[0069] If the engine speed of the vehicle 1 and the engine torque are not within the vibration damping region (No in step S21), it proceeds to step S23.

[0070] The calculation unit 32 calculates the upper limit of the battery output available for power and the like (step S23). That is, when the calculation unit 32 calculates the battery output reserved for performing the vibration damping control in step S22, the upper limit of the battery output available for power and the like is calculated by subtracting the reserved output from the total output. On the other hand, when the calculation unit 32 does not calculate the battery output reserved for performing the vibration damping control, the upper limit of the battery output is calculated assuming that there is no reserved battery output.

[0071] The control unit 34 controls the vehicle within a range that does not exceed the output upper limit of the available battery calculated in step S23 (step S24). That is, in the control unit 34, when a reserve of battery output for vibration control is necessary, the reserve is executed. Therefore, compared to the case where the reserve is not necessary, the output upper limit of the battery available for power, other electronic devices, etc. is in a reduced state.

[0072] As a result, in the region where vibration control is implemented, it is possible to reserve the battery output necessary for vibration control. Since whether to reserve the battery output is changed according to whether the state of the vehicle 1 is a region where vibration control is implemented, the battery output can be used efficiently.

[0073] Embodiment 3 In Embodiment 2, it was described that when it is a vibration control region where vibration control is implemented, the battery output is reserved so as to cover the magnitudes of both these amplitudes on both the Win side and the Wout side of the battery. However, in a situation where Win and Wout are each restricted and the necessary output cannot be reserved at low temperatures or in a low state of charge, it is considered that the hibernation vibration control cannot be implemented and the NV performance of the vehicle deteriorates.

[0074] Therefore, in Embodiment 3, a method will be described in which when the battery output for generating the torque necessary for vibration control cannot be reserved in the motor 12, the minimum engine speed is increased so that the NV performance of the vehicle does not deteriorate.

[0075] In addition, in Embodiment 3, similar to Embodiment 2, since a vehicle having the same configuration as the vehicle 1 described in Embodiment 1 is used, the same reference numerals are also given to each component article and the description is omitted. Regarding the vibration-with-NV line, vibration-free NV line, NV line, and vibration-ON line shown in FIG. 9 to be described later, since they are the same as those shown in FIG. 3, the description is omitted.

[0076] Referring now to FIG. 8, a procedure for suppressing deterioration of NV performance by increasing the minimum engine speed when power for vibration control cannot be reserved will be described.

[0077] The arithmetic unit 32 calculates the maximum battery output that wants to be reserved for vibration control in the current gear stage (step S31).

[0078] Here, the arithmetic unit 32 calculates the magnitude of the maximum battery output that wants to be reserved for performing vibration control by the motor 12 from the engine speed, the engine torque, and the vibration control torque upper limit.

[0079] Note that the maximum battery output that wants to be reserved is calculated so as to cover the magnitudes of both of these amplitudes on both the Win side and the Wout side of the battery, in the same manner as step S22 shown in Embodiment 2.

[0080] Next, in the vehicle 1, values of both the current battery Win and Wout are acquired (step S32). For example, the values of the battery Win and Wout are acquired by a sensor provided in the vehicle 1.

[0081] The determination unit 33 compares the maximum battery output that wants to be reserved, calculated in step S31, with the values of the current battery Win and Wout acquired in step S32, and determines whether it is possible to secure the maximum battery output that wants to be reserved (step S33).

[0082] When it is possible to reserve the maximum battery output required for vibration control (Yes in step S33), the battery output is reserved and the process ends.

[0083] When it is not possible to reserve the maximum battery output required for vibration control (No in step S33), the minimum engine speed in the current gear is increased (step S34).

[0084] Here, FIG. 9 shows the normal minimum rotational speed and the state where the minimum rotational speed is increased when the maximum battery output required for vibration control cannot be reserved. As shown in FIG. 9, the normal minimum rotational speed is lower than the rotational speed R1. And when the maximum battery output required for vibration control cannot be reserved, this minimum rotational speed can be increased to the rotational speed R2.

[0085] Specifically, in vehicle 1, when a predetermined engine torque is generated between the normal minimum rotational speed and the rotational speed R2, there is a portion where the relationship between the engine rotational speed and the engine torque is above the non-vibration NV line shown in FIG. 9. In this case, the NV performance of vehicle 1 deteriorates.

[0086] Therefore, in vehicle 1, the minimum rotational speed is increased to the rotational speed R2. That is, instead of generating a predetermined torque at a rotational speed lower than the rotational speed R2 under normal conditions, the same torque is generated with the engine torque increased to the rotational speed R2. As a result, the relationship between the engine rotational speed and the engine torque is likely to be below the non-vibration NV line shown in FIG. 9, and vehicle 1 is in a good state in terms of NV performance.

[0087] From the above, when the power for vibration control cannot be reserved, the deterioration of NV performance can be suppressed by increasing the minimum rotational speed of the engine until the condition for not executing vibration control is reached.

[0088] Note that the present invention is not limited to the above-described embodiments, and can be appropriately changed without departing from the gist. That is, the above description has been appropriately omitted and simplified for clarity of explanation, and those skilled in the art can easily change, add, and convert each element of the embodiments within the scope of the present invention.

[0089] In Embodiment 1, when the engine speed is lower than the speed R2, vibration control may or may not be performed, and it was described that vibration control is not performed at speeds of R2 or higher, but this is not restrictive. That is, there is no need to use the speed R2 as a threshold value. For example, the speeds R1 to R2 can be used as a threshold value.

[0090] Similarly for Embodiment 2, although the upper limit of the engine speed when providing the vibration control region was set to the speed R2, this is not restrictive.

[0091] Also, the increase in the minimum engine speed shown in Embodiment 3 was set to increase up to the speed R2, but this is not restrictive, and it may be set to increase the minimum engine speed until the vibration-free NV line shown in FIG. 9 sufficiently rises.

[0092] The contents described in Embodiment 1, Embodiment 2, and Embodiment 3 can be used by arbitrarily combining any plurality of them.

Explanation of Reference Numerals

[0093] 11 Internal combustion engine 12 Motor 13 Conversion unit 14 Wheel 21 Damper 22 Input shaft 23 Drive shaft 31 Storage unit 32 Arithmetic unit 33 Determination unit 34 Control unit

Claims

1. A control method for a hybrid vehicle that performs vibration damping control to remove vibration by applying torque that is out of phase with the damper torque to the motor, When rotating the engine at a predetermined rotational speed, it is determined whether the difference between the engine torque at which a predetermined vibration occurs when vibration damping control is performed and the engine torque at which a predetermined vibration occurs when vibration damping control is not performed is equal to or greater than a predetermined value, When the difference is equal to or greater than the predetermined value, when performing vibration damping control, the rotational speed of the engine is, a region where the difference between the engine torque at which a predetermined vibration occurs when the vibration damping control is performed and the engine torque at which a predetermined vibration occurs when the vibration damping control is not performed is equal to or greater than a predetermined torque, and the engine torque is, set as the region for performing vibration damping control a region that is less than or equal to the engine torque at which a predetermined vibration occurs when the vibration damping control is performed and greater than or equal to the engine torque at which a predetermined vibration occurs when the vibration damping control is not performed, In the region for performing the vibration damping control, the battery output required for vibration damping control is calculated using the rotational speed of the engine and the value of the vibration damping torque generated when performing vibration damping, Before performing the vibration damping control, reserve the calculated battery output required for the vibration damping control, A control method for a vehicle.

2. When the battery output required for the vibration damping control cannot be reserved, increase the rotational speed of the engine until the condition for not performing the vibration damping control is met, The control method for a vehicle according to claim 1.

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