WO2021251201A1

WO2021251201A1 - Electric vehicle control device

Info

Publication number: WO2021251201A1
Application number: PCT/JP2021/020748
Authority: WO
Inventors: 航輝宮下; 亮清水
Original assignee: 三菱自動車工業株式会社
Priority date: 2020-06-12
Filing date: 2021-05-31
Publication date: 2021-12-16
Also published as: JPWO2021251201A1; JP7306585B2

Abstract

When a shift position is switched between a forward range and a reverse range, an output torque command unit (5) of an electric vehicle control device according to the present invention carries out output reduction control that sets the output torque for an electric motor (22) to an output-mitigated torque that is lower than driver-requested torque. The output reduction control is canceled by an accelerator ON state in which the accelerator opening detected by an accelerator opening detection unit (2) is equal to or greater than a first prescribed value.

Description

Control device for electric vehicles

The present disclosure relates to a control device for an electric vehicle using an electric motor as a drive source.

In an electric vehicle that uses an electric motor as a drive source, when the shift position is selected to the forward range (drive range (D range), etc.) by the shift operation of the driver, the drive shaft of the electric motor rotates in the positive direction and the reverse range. When selected to (reverse range (R range)), the drive shaft of the electric motor rotates in the opposite direction. The rotation of the drive shaft of the electric motor is transmitted to the drive wheels via a speed reducer, a differential, or the like. At this time, when the drive shaft rotates in the forward direction, the vehicle moves forward, and when the drive shaft rotates in the opposite direction, the vehicle moves backward.

By the way, a large number of gears intervene in the power transmission path from the drive shaft of the electric motor to the drive wheels. There is a backlash in the meshing portion between the teeth of these gears, that is, a clearance caused by a gap or the like intentionally set in the movement direction of the member. For this reason, when the shift position is switched from the forward range to the reverse range, or when the vehicle starts immediately after the switch, first after the clearance at the meshing portion disappears (referred to as "playing"). The driving force may be transmitted to). When the clearance at the meshing portion is lost, the members that mesh with each other may collide strongly with each other, and sound or vibration may be generated. In addition, since these backlashes tend to increase as the members wear over time, the rattling noise and vibration may increase with the passage of time.

Therefore, Japanese Patent Application Laid-Open No. 2013-183503 describes the creep torque after the shift position is switched between the forward range and the reverse range while the vehicle is stopped or at a low vehicle speed, and before the vehicle starts. The technology of the control device which outputs the backlash filling torque smaller than that is disclosed. It is said that the output of this backlash filling torque can suppress the generation of noise and vibration generated from the meshing portion when the vehicle starts.

The control device of Japanese Patent Application Laid-Open No. 2013-183503 described above can suppress the generation of sound and vibration to some extent when the vehicle starts after switching the shift position. However, if you want to start as soon as possible after switching the shift position, the start time may be delayed or you may not be able to obtain satisfactory acceleration after starting.

The present disclosure provides a control device for an electric vehicle capable of suppressing the generation of sound and vibration after switching the shift position between the forward range and the reverse range, and appropriately responding to the subsequent start and acceleration. offer.

According to one aspect of the present disclosure, the control device of the electric vehicle includes an electric motor as a driving source for traveling, an accelerator opening detection unit for detecting the accelerator opening, and a shift position for detecting the selected shift position. A detection unit, a driver required torque calculation unit that calculates a driver required torque based on the accelerator opening degree, and an output torque command unit that commands an output torque to the electric motor are provided, and the output torque command unit is the said. When the shift position is switched between the forward range and the backward range, the output reduction control is performed to set the output torque to an output relaxation torque lower than the driver required torque, and the output reduction control is the accelerator opening. It is released when the accelerator is ON when the degree is equal to or higher than the first predetermined value.

According to the aspect of the present disclosure, after the output reduction control is released in the accelerator ON state, the increase rate of the output torque is set so as to correspond to the driver required torque based on the accelerator opening degree. The configuration may be adopted.

According to the aspect of the present disclosure, a braking device that generates a braking force based on the operation amount of the brake operation unit is further provided, and in the output reduction control, the output relaxation torque is reduced as the operation amount of the brake operation unit is smaller. A configuration may be adopted in which the duration to be set is set to be short.

According to the aspect of the present disclosure, a braking device that generates a braking force based on the operation amount of the brake operation unit is further provided, and in the output reduction control, the operation amount of the brake operation unit is a second predetermined value or more. A configuration may be adopted in which the duration for setting the output relaxation torque is set to be shorter in the braking release state in which the operation amount of the brake operation unit is less than the second predetermined value than in the braking state.

According to another aspect of the present disclosure, the control device of the electric vehicle includes an electric motor as a driving source for traveling, an accelerator opening detection unit for detecting the accelerator opening, and a shift for detecting a selected shift position. It is controlled based on the operation amount of the position detection unit, the driver required torque calculation unit that calculates the driver required torque based on the accelerator opening, the output torque command unit that commands the output torque to the electric motor, and the brake operation unit. The output torque command unit includes a braking device that generates power, and the output torque command unit reduces the output torque to a torque lower than the driver required torque when the shift position is switched between the forward range and the backward range. The output reduction control set to the torque is performed, and the output reduction control is set so that the smaller the operation amount of the brake operation unit is, the shorter the duration for setting the output relaxation torque is.

FIG. 1 is a time chart showing a first control example of one embodiment in the present disclosure. FIG. 2 is a time chart showing a second control example of one embodiment. FIG. 3 is a time chart showing a third control example of one embodiment. FIG. 4 is a flowchart showing a control example. FIG. 5 is a schematic diagram of a vehicle and a vehicle control device.

The embodiments in the present disclosure will be described with reference to FIGS. 1 to 5. In this embodiment, when the driver switches the shift position between the forward range and the reverse range in a low speed region such as when the vehicle 20 is traveling at a low speed or when the vehicle 20 is stopped, the power transmission path is It is a control device 10 for an electric vehicle that suppresses the generation of noise and vibration in the electric vehicle and appropriately responds to the subsequent start and acceleration.

Here, the low speed range is a state in which the vehicle speed, that is, the speed of the vehicle 20 is a minute vehicle speed of a predetermined speed or less, and the driver operates the shift lever 26 to change the shift position from the forward range to the reverse range via the neutral range. Or, it means an extremely low speed state (including forward and backward) in which the reverse range is switched to the forward range via the neutral range, or a stopped state of the vehicle 20. Hereinafter, the neutral range is referred to as an N range. Further, the forward range means a forward travel range such as a drive range (D range) and a second range (2 range) in which forward drive torque is applied to the

drive wheels

28 and 29, and the backward range is defined as a backward range. It means a reverse range (R range) to which a reverse drive torque is applied.

In general, a shift change from the D range to the R range via the N range or a shift change from the R range to the D range via the N range causes the vehicle 20 to stop completely at a vehicle speed of 0 km / h. It is desirable to carry out such a shift change, but in many cases, the driver is allowed to make such a shift change in the driving state of a low vehicle speed. The predetermined speed that defines the low speed range means the maximum vehicle speed (for example, about 2 to 3 km / h) at which such a shift change is allowed.

FIG. 5 is a schematic diagram of a vehicle (electric vehicle) 20 on which the control device 10 according to the present embodiment is mounted. The vehicle 20 is an electric vehicle provided with an electric motor 22 that generates a driving force by electric power, and is a plug-in hybrid electric vehicle in the present embodiment. When the engine 24 drives a generator to exert a power generation function, electric power is supplied to the electric motor 22 which is a driving source for traveling, and electricity is stored in the storage battery 23. Further, the storage of electricity in the storage battery 23 is also performed by connecting the vehicle 20 and the power source on the ground side with a dedicated cable. In the present embodiment, the electric motor 22 includes a front motor 22a and a rear motor 22b, and the front motor 22a and the rear motor 22b separately drive both the front wheels and the

rear wheels

28 and 29 via the differential 27, respectively. However, the vehicle 20 may drive all the

drive wheels

28 and 29 with one electric motor 22.

Brake units 31 equipped with brake discs, brake calipers, etc. are mounted on the left and right

front wheels

28, 28 and the left and right

rear wheels

29, 29 of the vehicle 20, respectively. The brake unit 31 generates braking force on the

drive wheels

28 and 29 based on the operation amount of the brake operation unit 30. These brake units 31, the brake operation unit 30, and the brake control unit 7 that controls them constitute a braking device for the vehicle 20. Normally, the driver's seat is equipped with a brake pedal (hereinafter referred to as a brake pedal 30) as the brake operation unit 30, and the depression amount or depression strength of the brake pedal 30 serves as a reference for determining the strength of the braking force. It is said to be a quantity. Further, at the time of braking, the electric motor 22 functions as a generator by the rotation reversely input from the

drive wheels

28 and 29, and electric power is regenerated.

The vehicle control device 10 determines the speed detection unit 1 that detects the vehicle speed, the accelerator opening detection unit 2 that detects the accelerator opening based on the information from the accelerator position sensor, and the shift position selected based on the information from the shift position sensor. It includes a shift position detection unit 3 for detection, a driver required torque calculation unit 4 for calculating a driver required torque based on an accelerator opening degree, and an output torque command unit 5 for commanding an output torque for an electric motor. These are provided in the electronic control unit (Electronic Control Unit) 21. Further, the vehicle 20 is provided with sensors for detecting various information necessary for driving control, such as a torque sensor for detecting the output torque from the electric motor 22 and a sensor for detecting the amount of depression of the brake pedal. .. Information from these sensors is transmitted to the control unit 6 that controls the overall control of the electronic control unit 21. The electronic control unit 21 also includes a brake control unit 7.

The speed detection unit 1 detects the traveling speed of the vehicle 20 based on the information from the vehicle speed sensors provided on the

drive wheels

28, 29 and the like. The accelerator opening degree detecting unit 2 can detect the accelerator opening degree, that is, the amount of depression of the accelerator pedal 25 by the driver with a numerical value between 0% and 100%. Here, 0% is a state in which the accelerator pedal 25 is not depressed at all, and 100% is a state in which the accelerator pedal 25 is fully depressed. Based on this accelerator opening degree, the driver required torque calculation unit 4 can detect the presence / absence of an acceleration request for the vehicle 20 and the magnitude of the acceleration request (accelerator required torque).

The shift position detection unit 3 detects the shift position of the automatic transmission based on the information from the shift position sensor that detects the position of the shift lever 26. Further, when the shift position is switched, the switching information is transmitted to the electronic control unit 21. Therefore, for example, when the shift position is switched from the D range to the N range, from the N range to the R range, or from the R range to the N range, and from the N range to the D range, the change is said to have occurred. Information is transmitted to the control unit 6 of the electronic control unit 21. The information that the shift position has been switched may be, for example, a signal indicating the switching transmitted at the time of the switching, or the shift position may be changed every minute constant time (for example, every 0.01 seconds). If the shift position signal is the same between the previous judgment and the current judgment, there is no switching, and if the shift position signal is different, it is judged that there was a switch. You may try to do it. The shift position information includes information on where the current shift position is and information on the shift position being switched as described above.

Here, if it is determined that there has been a switch from the D range to the R range via the N range or from the R range to the D range via the N range within a predetermined detection time set in advance, the shift position is determined. The detection unit 3 determines that the shift position has been switched back and forth. The predetermined detection time for determining the presence / absence of front / rear switching may be, for example, a minute fixed time, which is the transmission interval of the above-mentioned shift position signal, or a time that is an integral multiple of the minute fixed time. can.

The output torque command unit 5 has a function of commanding the output torque to the electric motor 22. FIG. 4 shows the calculation of the output torque by the output torque command unit 5 and the flow of the command. Reference numerals p1 and p2 in the figure are information on accelerator required torque and creep torque calculated based on the accelerator opening degree (accelerator position sensor voltage), respectively. The accelerator required torque and creep torque are calculated by the driver required torque calculation unit 4 based on information on the accelerator opening degree, information from the torque sensor, and various other information indicating the operating state. Further, the driver required torque calculation unit 4 calculates the driver required torque based on the information such as the accelerator required torque and the creep torque (see step s1).

Subsequently, it is determined whether or not the shift position is switched back and forth. Whether or not to perform output reduction control is determined based on the presence or absence of the front-back switching (see step s2). In the normal operating state without switching the shift position back and forth, the output reduction control is not performed. If the shift position is switched back and forth, the output reduction control is started.

The output torque command unit 5 commands the output torque to the electric motor 22 by commanding the increase rate of the output torque with respect to the output torque at that time (see steps s3 and s4). In normal control, as a general rule, it is commanded by an index of how much the current output torque should be increased or decreased in order to match the current output torque with the driver's required torque, that is, the required torque increase rate. .. In addition, in the output reduction control, an output relaxation torque that is relatively lower than the driver required torque is adopted. In principle, in order to match the current output torque with the output relaxation torque, the ratio of the current output torque is adjusted. It is commanded by the index of whether to increase or decrease, that is, the torque increase rate during relaxation. By performing output reduction control, it is possible to suppress the sound and vibration generated after switching the shift position between the forward range and the backward range.

Further, the output reduction control is canceled even during the control if the accelerator is turned on when the accelerator opening becomes the first predetermined value or more during the duration in which the output relaxation torque is set. Whether or not the accelerator opening degree is in the accelerator ON state is determined by whether or not the accelerator opening degree is equal to or higher than the first predetermined value which is the accelerator ON threshold value. Here, the first predetermined value can be, for example, 5%, which is obtained by adding pedal play to the accelerator opening degree of 0%. Since the output reduction control is released in the accelerator ON state, it is possible to appropriately respond to the start and acceleration required by the driver thereafter.

In step s5 of FIG. 4, the required motor torques for the front and rear

electric motors

22a and 22b are calculated based on the calculated output torque and the information of the increase rate of the output torque (required motor shown by reference numeral p3). Torque (front), required motor torque (rear) indicated by reference numeral p4).

FIG. 1 is a time chart showing a first control example of one embodiment in the present disclosure. A first control example of the present disclosure will be described with reference to the time chart of FIG. It is assumed that the shift position is switched from the R range to the D range via the N range at the a0 point indicated by the symbol (a) in FIG. At this time, at the point b0 shown by the symbol (b) in FIG. 1, the stroke (depression amount) of the brake pedal 30 is positive, and the brake ON state in which the braking force is applied slightly strongly to the extent that the vehicle 20 stops. .. Further, at the c0 point shown by the symbol (c) in FIG. 1, the accelerator opening degree is zero and the accelerator is OFF. Further, as shown by the symbol (d) in FIG. 1, the vehicle speed is an operating state in a low speed range of almost zero. When the shift position is switched back and forth at the a0 point, the output torque is a creep torque as indicated by the symbol e1 in the symbol (e) in FIG. The brake ON state is defined as a braking state in which the amount of depression of the brake pedal 30 (the amount of operation of the brake operation unit) is equal to or higher than a predetermined second predetermined value, and the brake OFF state is defined as the depression of the brake pedal 30. It can be defined as a braking release state in which the amount (the amount of operation of the brake operating unit) is less than the second predetermined value. The second predetermined value may be, for example, the depression amount of the brake pedal 30 (the operation amount of the brake operation unit) may be zero, or may be set to a positive value in consideration of the play of the pedal or the like until the brake actually starts to work. You may.

By switching the shift position back and forth, the state (or status) of the shift position rises from -1 (corresponding to the R range) to 1 (corresponding to the D range) as indicated by the symbol f0 in the symbol (f) in FIG. .. That is, the positive sign of torque indicates forward, and the negative sign indicates reverse. The solid line g2 shown by the symbol (g) in FIG. 1 is the required motor torque corresponding to the output torque after the output reduction control is performed, and the chain line g1 is the required motor corresponding to the driver required torque before the output reduction control is performed. It is torque. Although the symbol (g) in FIG. 1 illustrates the state of the front motor, the same control can be performed with the rear motor. The required motor torque commanded to the electric motor 22 is reduced from the chain line g1 shown by the symbol (g) in FIG. 1 to the solid line g2. Here, when it is determined that the output reduction control should be performed, the MAP for limiting the increase rate of the output torque for each drive mode, which is normally used, is switched to the suppression MAP for the output reduction control, and each operating state is selected. A command for the rate of increase is issued according to the above.

The output relaxation torque indicated by the solid line g2 in the symbol (g) in FIG. 1 remains almost unchanged or slightly increases when the shift position is switched back and forth (the torque increase rate during relaxation changes at zero or near zero), and then. , The output relaxation torque gradually increases (the torque increase rate during relaxation also gradually increases), and the amount of increase in the output relaxation torque per unit time decreases or increases near the torque zero where the drive direction of the electric motor 22 reverses back and forth. The amount becomes zero once, that is, it becomes flat with a smaller increase amount than before and after (the torque increase rate at the time of relaxation decreases or becomes zero once). Such a section in a flat state near zero torque is referred to as an output torque adjustment section, and in this control example in the brake ON state, the output torque adjustment section is set for time t1. Here, the output torque adjustment section can be defined within a range in which the amount of change in output per unit time is small, in which the rate of increase in output relaxation torque is less than a preset predetermined rate of increase. When the output relaxation torque passes the output torque adjustment section, the output relaxation torque gradually increases (the torque increase rate during relaxation also gradually increases), and the unit time is before approaching the driver required torque after reversal indicated by the chain line g1. The amount of increase in the output relaxation torque per hit decreases (the torque increase rate during relaxation decreases), and finally the output relaxation torque reaches the driver required torque and the control ends. The time t2 in the figure is the time required between the inflection points of the increase rate of the output torque. The chain line h2 of the symbol (h) in FIG. 1 indicates the acceleration of the vibration of the vehicle 20 that occurs when the output reduction control is not performed (the increase in torque at the g0 point in the figure is the vibration of the chain line h2 as shown by the arrow B). The solid line h1 indicates the acceleration of the vibration of the vehicle 20 when the output reduction control is performed. By the output reduction control, the maximum amplitude of the vibration of the vehicle 20 is significantly reduced from y0 to y1.

FIG. 2 is a time chart showing a second control example of one embodiment. A second control example of the present disclosure will be described with reference to the time chart of FIG. The second control example assumes a case where the accelerator is turned on when the accelerator opening degree becomes the first predetermined value or more after the output reduction control is started. When the accelerator is turned on, the output reduction control is canceled. Since the control until the output reduction control is started is the same as that in FIG. 1, the description thereof will be omitted. In addition, "'" is attached to the code in FIG. 2, and the reference numerals a0', b0', c0', f0', g0', arrow A'and the like in FIG. 2 are shown in FIG. It corresponds to the reference numerals a0, b0, c0, f0, g0, and the arrow A and the like.

After shifting to the accelerator ON state and releasing the output reduction control, normally, the output torque will be restored without the output reduction control. However, when the output reduction control is completed and the output torque is suddenly returned to the value before the reduction correction, the output torque is discontinuously fluctuated, which leads to deterioration of riding comfort. Therefore, when the accelerator is turned on, the increase rate of the output torque is set according to the driver required torque based on the accelerator opening degree.

Here, since the output torque at the time of acceleration after the output reduction control is released is determined based on the normal output torque increase rate (required torque increase rate) based on the accelerator opening, the symbol in FIG. 2 ( As shown by the symbol g3', the torque increases with the same slope as the degree of increase in the torque when there is no output reduction control indicated by the symbol g1'in g). After that, the torque increase control continues based on the accelerator operation, and the control ends when the acceleration ends. In this control when the accelerator is ON, the time t1'in the output torque adjustment section near zero torque is shorter than the time t1 when the brake is ON in FIG. 1, and the time required between the inflection points of the increase rate of the output relaxation torque is t2. 'Is also set shorter than the time t2 when the brake is turned on in FIG. 1, and corresponds to early acceleration. Further, the maximum value of the increase rate during the time t1'in the output torque adjustment section is larger than that of the first control example in FIG. 1 (the slope of the increase is large).

FIG. 3 is a time chart showing a third control example of one embodiment. A third control example of the present disclosure will be described with reference to the time chart of FIG. The third control example assumes a case where the brake is OFF when the output reduction control is started. In the brake OFF state, even if the brake pedal 30 is not operated or is depressed, the amount of depression is about play, and the brake is not substantially operated. Therefore, it is a driving state in which the driver is expected to immediately operate the accelerator. Since the main part is the same as the control when the brake is turned on in FIG. 1, the description thereof will be omitted, and the differences related to the ON / OFF of the brake will be mainly described below. In addition, "" "is added to the code in FIG. 3 to distinguish it from the code of the corresponding portion in FIG.

In the third control example, the time t1 "in the output torque adjustment section is shorter than the time t1 when the brake is turned on in FIG. 1, and the time t2" between the inflection points of the increase rate of the output relaxation torque is also shown in FIG. It is set shorter than the time t2 when the brake is turned on, and is prepared for the demand for acceleration that is expected to be performed subsequently. Further, in the output reduction control, not only the output torque adjustment section but also the duration for setting the output relaxation torque, the duration t0 ”for setting the output relaxation torque in the OFF state of the brake is the output relaxation in the brake ON state. It is set shorter than the duration t0 for setting the torque. Here, the time t1, t1 "in the output torque adjustment section, the required time t2, t2" between the variation points of the increase rate of the output relaxation torque, and the output relaxation. The control has been described for each of the durations t0 and t0 "in which the torque is set, in two stages of whether the brake is on or off. However, the control is not limited to this example, and for example, the brake pedal 30 may be used. A control set may be adopted so that the smaller the stepping amount (the operating amount of the brake operating portion) is, the shorter the stepping amount is gradually or steplessly and continuously.

In each of the above control examples, the content of the control is explained assuming that the shift position is switched from the R range to the N range and then to the D range. However, the shift position is from the D range to the N range and then to the R range. Even when it is switched to, the same control with the drive direction reversed is possible. Further, in the present embodiment, the plug-in hybrid electric vehicle is adopted as the vehicle 20, but in addition to the present embodiment, the present disclosure is disclosed in various electric vehicles provided with an electric motor 22 that generates a driving force by electric power. Applicable.

This application is based on Japanese Patent Application No. 2020-102134 filed on June 12, 2020, the contents of which are incorporated herein by reference.

1 Speed detection unit 2 Accelerator opening detection unit 3 Shift position detection unit 4 Driver required torque calculation unit 5 Output torque command unit 10 Vehicle control device 20 Vehicle 21 Electronic control unit 22 Electric motor

Claims

An electric motor, which is a driving source for driving,
Accelerator opening detection unit that detects the accelerator opening, and
A shift position detector that detects the selected shift position,
A driver required torque calculation unit that calculates the driver required torque based on the accelerator opening, and a driver required torque calculation unit.
It is provided with an output torque command unit that commands the output torque for the electric motor.
The output torque command unit performs output reduction control to set the output torque to an output relaxation torque lower than the driver required torque when the shift position is switched between the forward range and the backward range.
The output reduction control is a control device for an electric vehicle that is released in an accelerator ON state in which the accelerator opening degree is equal to or greater than a first predetermined value.
The electric vehicle according to claim 1, wherein the increase rate of the output torque is set so as to correspond to the driver required torque based on the accelerator opening degree after the output reduction control is released in the accelerator ON state. Control device.
It is further equipped with a braking device that generates braking force based on the amount of operation of the brake operation unit.
The control device for an electric vehicle according to claim 1, wherein the output reduction control is set so that the smaller the operation amount of the brake operation unit is, the shorter the duration for setting the output relaxation torque is.
It is further equipped with a braking device that generates braking force based on the amount of operation of the brake operation unit.
The output reduction control is the output relaxation torque in the braking release state in which the operation amount of the brake operation unit is less than the second predetermined value than in the braking state in which the operation amount of the brake operation unit is equal to or more than the second predetermined value. The control device for an electric vehicle according to claim 1, wherein the duration is set to be short.
An electric motor, which is a driving source for driving,
Accelerator opening detection unit that detects the accelerator opening, and
A shift position detector that detects the selected shift position,
A driver required torque calculation unit that calculates the driver required torque based on the accelerator opening, and a driver required torque calculation unit.
An output torque command unit that commands the output torque for the electric motor,
It is equipped with a braking device that generates braking force based on the amount of operation of the brake operation unit.
The output torque command unit performs output reduction control to set the output torque to an output relaxation torque lower than the driver required torque when the shift position is switched between the forward range and the backward range.
The output reduction control is a control device for an electric vehicle set so that the smaller the operation amount of the brake operation unit is, the shorter the duration for setting the output relaxation torque is.