JP3183121B2 - Electric car - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric vehicle in which wheels are driven by an electric motor and travels, and more particularly to an electric vehicle with improved torque control of the motor.

[0002]

2. Description of the Related Art In recent years, electric vehicles have attracted attention from the viewpoint of preventing air pollution and reducing noise caused by vehicles. In such an electric vehicle, similarly to a conventional vehicle such as a gasoline engine, the output torque (powering torque) of the motor is controlled in accordance with the accelerator opening (accelerator depression amount). Further, in an electric vehicle, so-called regenerative braking can be easily performed, and the regenerative braking is configured to control the regenerative torque of the motor in accordance with a brake opening (a brake depression amount or a brake operating state). .

[0003] Some electric vehicles also include a transmission. Conventionally, however, the power running torque of the motor is limited to the accelerator opening or the brake opening regardless of the selected gear position (shift position). Alternatively, it is configured to control the regenerative torque. For example, FIG. 5 shows a characteristic of a motor running torque command value or a regenerative torque command value of a motor in a conventional electric vehicle with a two-speed transmission.
Regardless of the speed (first speed) or the second speed (second speed), the power running torque or the regenerative torque of the motor is commanded and controlled only for the accelerator opening or the brake opening.

As a result of controlling the power running torque or the regenerative torque of the motor in this way, the driving force of the vehicle output through the transmission is, as shown in FIG. It decreases depending on the ratio and the gear efficiency. That is, the driving force or the braking force in the case of the second speed has the following relationship with the driving force or the braking force in the case of the first speed.

Second-speed driving force (or second-speed braking force) = first-speed driving force (or first-speed braking force) × {(r2 × e2) / (r1 × e1)} (1) , R1: 1st gear ratio, e1: 1st gear efficiency r2: 2nd gear ratio, e2: 2nd gear efficiency Since (r2 × e2) <(r1 × e1), the second speed driving force is shown in FIG. Thus, the driving force is smaller than the first-speed driving force.

The motor torque (motor running torque or regenerative torque) has characteristics as shown in FIG. 7, and the region where the motor speed is low is a constant torque region where the torque is constant. The region where the rotational speed is high is a constant output region where the motor output is constant. In this constant output area,
As shown in the figure, the torque decreases as the motor speed increases.

[0007]

However, like the conventional electric vehicle, the motor torque (power running torque of the motor or the regenerative torque) only for the accelerator opening or the brake opening is conventionally independent of the selected gear position. Controlling the torque) has the following disadvantages. That is, if the accelerator opening is constant before and after the shift change, the motor torque becomes constant before and after the shift change as shown in FIG.
On the other hand, the driving force greatly changes as shown in FIG. Therefore, if a gear change operation is performed with the accelerator opening kept constant, the driving force changes abruptly, and the driving feeling deteriorates.

In order to perform comfortable gear shifting, it is necessary to keep the driving force constant before and after the shift change. To this end, the driver appropriately increases or decreases the accelerator pedal depression amount before and after the shift change. Inevitably, there is a problem that a driver is burdened with a driving operation.
By the way, for example, Japanese Patent Laid-Open Publication No. Hei 6-98420 discloses a technique for improving the switching feeling at the time of changing gears in an electric vehicle. This is related to processing, and such a technique cannot solve the above-described problem.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and has as its object to provide an electric vehicle capable of performing a comfortable gear shift without depending on a driver's driving operation. .

[0010]

According to the present invention, an electric vehicle according to the present invention is provided with a transmission having at least two or more alternately selected speeds, and a transmission via the transmission. An electric motor having an output shaft connected to driving wheels of the vehicle and electrically connected to a battery mounted on the vehicle;
Operating state detecting means having a shift position detecting means for detecting a shift speed of the transmission and an accelerator opening detecting means for detecting an accelerator opening; and various detection information from the shifting position detecting means and the accelerator opening detecting means. Control means for controlling a torque generated in the electric motor in accordance with the accelerator opening so that a driving force generated in the drive wheels becomes equal before and after performing a shift operation of the transmission at an equal accelerator opening. And the control means controls the shift position detecting means.
Based on each detection information from gear and accelerator opening detection means
A calculating unit for calculating the magnitude of the target torque of the electric motor,
The target torque calculated by the calculation unit is generated by the motor.
If the value is larger than the maximum torque that can be
A restricting means for restricting the target torque within the maximum torque.
And the target torque is the maximum torque.
In order to gradually approach the maximum torque in the vicinity of
It is characterized in that a correction means for correcting the target torque is provided .

[0011]

[0012] Incidentally, the said operating condition detecting means comprises a brake operation detecting means for detecting an operating state of the brake, the control means, the operating state of the electric motor, is electric motor drives the drive wheel traction An operation state and a regenerative operation state in which the electric motor performs a regenerative operation by the rotational force transmitted from the drive wheels are switched, and when the electric motor is in the regenerative operation state, the shift position detecting means and the accelerator opening are set. Based on each detection information from the detecting means, the torque generated in the electric motor is determined by the accelerator opening so that the driving force generated in the drive wheels becomes equal before and after performing the shift operation of the transmission at the same accelerator opening. and it may be added so that the configuration includes a control means for controlling in response to.

In this case, the control means calculates a target torque of the electric motor based on each detection information from the shift position detecting means and the accelerator opening degree detecting means. When the calculated target torque is a value larger than the maximum regenerative torque that can be generated by the electric motor, a limiting means for restricting the target torque within the maximum regenerative torque may be provided .

Further , the target torque gradually approaches the maximum regenerative torque in the vicinity of the maximum regenerative torque.
Correction means for correcting the target torque may be provided .

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 to 4 show an electric vehicle as an embodiment of the present invention. First, the configuration of the present apparatus will be described. In FIG. 1, reference numeral 1 denotes a battery, and this battery 1 can be repeatedly charged by an external charger not provided in the vehicle. Reference numeral 2 denotes an electric motor (running motor) supplied with electric power from the battery 1. The output shaft of the motor 2 is connected to a driving wheel 4 via a transmission 3.
Are connected. Here, the transmission 3 is a two-stage transmission having a first speed (first speed) and a second speed (second speed).

A power conversion circuit 5 is provided between the battery 1 and the motor 2. The power from the battery 1 is adjusted to a required magnitude through the power conversion circuit 5 and supplied to the motor 2. It has become so. This power conversion circuit 5 is controlled through a motor controller 6. The motor controller 6 controls the output of the motor 2 through the power conversion circuit 5 according to the depression amount of an accelerator pedal (not shown).

The motor controller 6 includes a motor torque control unit 7. The motor torque control unit 7 controls the output torque of the motor. For this purpose, the motor torque control unit 7 includes a storage unit 8, a determination unit 9, a calculation unit 10, and an instruction unit 11. ing. The motor torque control unit 7 includes operating state detecting means 20, that is, a brake opening detecting means 21 as a braking operation detecting means, an accelerator opening detecting means 22 as an accelerator position detecting means, and a shift position detecting means 2.
7 is connected, and brake operation information, accelerator operation information, and shift position information are input.

As described above, the motor torque control includes a case where the output torque (power running torque) of the motor is controlled and a case where the regenerative torque of the motor is controlled. The operation is performed in accordance with the accelerator opening (accelerator depression amount) and the selected gear position, and the regenerative torque command is performed in accordance with the brake opening amount (brake depression amount) and the selected gear position. Is configured.

That is, as shown in FIG. 2, the motor torque control is basically performed so that the motor torque increases in accordance with the increase in the accelerator opening or the brake opening. In the region where the opening degree is equal to or less than a certain value, the motor torque is set to be larger in the second speed than in the first speed. This is because in this electric vehicle, if the driving force or the braking force of the vehicle output through the driving system such as the motor 2 and the transmission 3 is constant at the accelerator opening or the brake opening, the gear position (ie, the first gear) Or 2nd gear) is set to be constant.

That is, since the driving force or the braking force in the case of the second speed is related to the driving force or the braking force in the case of the first speed as in the above equation (1), the accelerator opening in the first speed is performed. Motor torque command value (powering torque command value or regenerative torque command value) for the degree or brake opening is set as in the following equation (2), and the motor torque command for the accelerator opening or the brake opening at the second speed is set. The value is set on the basis of a command value such as Expression (3).

First speed torque command = a × accelerator opening or brake opening (2) Second speed torque command (basic command value) = a × accelerator opening or brake opening × ｛(r1 × e1) / (r2 × e2)｝ (3) where, r1: 1st gear ratio, e1: 1st gear efficiency r2: 2nd gear ratio, e2: 2nd gear efficiency When the motor torque command value for the second speed is set as described above, the motor torque command value reaches 100% before the accelerator opening or the brake opening is fully opened. Therefore, after this, even if the accelerator opening or the brake opening increases, the motor torque command value is reduced by 100%.
It is configured to limit to%.

For this reason, a map or a table for calculating the basic command value is stored in the storage means 8, and the determining means 9 can determine whether the motor torque command value has reached 100%. Has become. The calculating means 10 includes a calculating section 10A for calculating a basic command value and a limiting section (limiting means) 10 for limiting the motor torque command value to 100%.
B is provided.

By the way, if the above-mentioned basic command value is used as it is as the motor torque command value at the second speed, when the motor torque command value reaches 100%, the increase rate of the command value suddenly changes. Become. In this case, it is considered that a sense of incongruity occurs. Therefore, in the electric vehicle, the motor torque command value changes smoothly in the vicinity of the motor torque command value reaching 100%, and is set so as to approach 100%. I have.

That is, the accelerator opening or brake opening θ
However, when the basic command value (see equation (3)) reaches a predetermined value (= θ0−α) that is a predetermined amount α before the accelerator opening or the brake opening (this is assumed to be θ0) at which 100% is obtained. ,
Until the accelerator opening or the brake opening reaches θ0 so as to correspond to the basic command value of 100%, the correction amount C1 according to the increase amount (Δθ1) of the accelerator opening or the brake opening.
(= B · Δθ1, b: proportional constant) is subtracted from the basic command value. Then, after the accelerator opening or the brake opening reaches θ0, a correction amount C2 (= b · Δθ1−b · Δ) corresponding to the increment (Δθ2) of the accelerator opening or the brake opening.
θ2, b: proportional constant) is subtracted from the basic command value.

As a result, as shown in FIG. 2, the motor torque command value gradually approaches a value of 100% while smoothly changing to a curve in the vicinity of the value at which the motor torque command value reaches 100%. . For this reason, the judging means 9 judges whether the motor torque command value has reached this correction range, and the calculating means 10 corrects the motor torque command value by such calculation processing. A correction unit (correction means) 10C that changes the value smoothly in a curved shape is provided.

Since the electric vehicle according to one embodiment of the present invention is configured as described above, the torque of the motor is controlled at a predetermined cycle, for example, as shown in the flowchart of FIG. That is, the shift position is determined in step S10, and then, in step S20, a torque command value (basic command value) is calculated according to the shift position and the accelerator opening or the brake opening.

Here, the torque command value (basic command value) is 1
It is determined whether the torque command value is equal to or more than 00% (maximum command value) (step S30). If the torque command value (basic command value) is 100% (maximum command value) or more, the torque command value is 100% (maximum command value). (Step S40). Further, a correction process is performed so that the motor torque command value changes smoothly near the motor torque command value reaching 100% (step S50), and based on the set torque command value as described above. Thus, a torque command is output from the command means 11.

As described above, in this electric vehicle, the motor 2
And the driving force or the braking force of the vehicle output through the driving system such as the transmission 3 is constant regardless of the gear position (that is, the first speed or the second speed) if the accelerator opening or the brake opening is constant. Since the motor torque is controlled so that the accelerator opening or the brake opening is medium or less in a normal use region, if the accelerator opening is constant before and after the shift change,
As shown in FIG. 3, the driving force or the braking force is constant before and after the shift change, and the speed change operation can be performed with a good feeling with no change in the driving force and the braking force.

Therefore, the burden on the driver to increase or decrease the depression amount of the accelerator pedal before and after the shift change is reduced, and the driving operation of the driver can be made easier, and the driver's fatigue due to the driving operation can be reduced. Note that, in the present embodiment, a two-stage transmission is taken as an example, but the present invention is not limited to the transmission gear stage. Therefore, if the motor torque command value for the accelerator opening or the brake opening at the second speed is set as in the above equation (2), the motor torque command value for the accelerator opening or the brake opening at the nth speed is given by the following equation. A command value such as (4) can be basically set.

N-speed torque command (basic command value) = a × accelerator opening or brake opening × {(r1 × e1) / (rn × en)} (4) where r1: 1 Speed gear ratio, e1: 1 speed gear efficiency rn: n speed gear ratio, en: n speed gear efficiency Of course, also in this case, when the basic command value becomes 100%, the accelerator opening or the brake opening increases. Also, the torque command value is limited to 100%. When the torque command value is 1
It is desirable that the torque command value be asymptotically approached to 100% so that the torque command value can be smoothly transitioned to 00%.

In this embodiment, the torque command value is limited or corrected by the calculation of the calculation means 10. However, the torque command value for the accelerator opening or the brake opening is set and stored in a map or a table. In addition, the torque command value may be set according to the accelerator opening or the brake opening based on this map or table. Of course, the map or table in this case is shown in FIG.
Are set so as to have the characteristics shown in FIG.

When the torque command value approaches 100%, the curved portion as shown in FIG. 2 may be approximated by a polygonal line having an appropriate interval. further,
The present invention is applicable whether the transmission is an automatic transmission or a manual transmission.

[0033]

As described above in detail, according to the electric vehicle of the first aspect of the present invention, there is provided a transmission having at least two or more alternately selected shift speeds, and An output shaft is connected to driving wheels of the vehicle via an electric motor, and is electrically connected to a battery mounted on the vehicle, a shift position detecting means for detecting a shift speed of the transmission, and an accelerator opening. Operating state detecting means having an accelerator opening detecting means for detecting, and before and after performing a shift operation of the transmission at the same accelerator opening based on each detection information from the above-mentioned shift position detecting means and accelerator opening detecting means. And a control means for controlling the torque generated in the electric motor in accordance with the accelerator opening so that the driving forces generated in the driving wheels become equal. Is reduced accelerator operation burden at the time of power running, it is possible to realize the switching of good gear stage smooth and feeling while facilitating a driving operation of the driver.

According to the electric vehicle of the first aspect of the present invention , the control means further determines the target torque of the electric motor based on the detection information from the shift position detecting means and the accelerator opening degree detecting means. A calculation unit for calculating the magnitude, and a restriction for restricting the target torque within the maximum torque when the target torque calculated by the calculation unit is larger than the maximum torque that can be generated in the electric motor. With this configuration, the torque is set in a controllable range during power running, and smooth torque control is realized.

According to the first aspect of the present invention, there is further provided a correcting means for correcting the target torque such that the target torque gradually approaches the maximum torque near the maximum torque. With this configuration, output adjustment is performed more smoothly during power running, and riding comfort is improved. The operating state detecting means has a brake operation detecting means for detecting an operating state of the brake, and the control means determines an operating state of the electric motor as a power running operating state in which the electric motor drives the driving wheels. Switching between a regenerative operation state in which the electric motor performs a regenerative operation by the rotational force transmitted from the drive wheels, and when the electric motor is in the regenerative operation state, the shift position detection means and the accelerator opening degree detection means Based on the respective detection information, the torque generated in the electric motor is adjusted according to the accelerator opening so that the driving force generated in the drive wheels becomes equal before and after performing the shift operation of the transmission at the same accelerator opening. if configured with a control means for controlling, is reduced accelerator operation burden of the driver at the shift change before and after, during regenerative, Do to facilitate driving operation of the driver It is possible to realize the switching of good gear stage La smooth and feeling.

In this case, the control means calculates a target torque of the electric motor based on each detection information from the shift position detecting means and the accelerator opening degree detecting means. when calculated target torque is larger than the maximum regenerative torque can be generated in the electric motor, when equipped with a limiting means for restricting the target torque within said maximum regenerative torque, during regenerative, controllable The torque is set within a proper range, and smooth torque control is realized.

Further, the target torque gradually approaches the maximum regenerative torque in the vicinity of the maximum regenerative torque.
When correction means for correcting the target torque is provided, at the time of regeneration, more smoothly output adjustment is performed, ride comfort is improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an electric vehicle as one embodiment of the present invention.

FIG. 2 is a diagram illustrating a motor torque setting characteristic of an electric vehicle according to an embodiment of the present invention.

FIG. 3 is a diagram showing characteristics of driving force generation by an electric vehicle as one embodiment of the present invention.

FIG. 4 is a flowchart showing motor control by an electric vehicle as one embodiment of the present invention.

FIG. 5 is a characteristic diagram of a reference gain for setting a basic regenerative braking force by a conventional electric vehicle.

FIG. 6 is a diagram showing a setting characteristic of a motor torque by a conventional electric vehicle.

FIG. 7 is a diagram showing torque characteristics of a motor.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Battery 2 Electric motor (running motor) 3 Transmission 4 Driving wheel 5 Power conversion circuit 6 Motor controller 7 Motor torque control part (control means) 8 Storage means 9 Judgment means 10 Calculation means 10A Calculation part 10B Limiting part (Limiting means) 10C Correction unit (correction means) 11 Instruction means 20 Operating state detection means 21 Brake opening degree detection means as brake operation detection means 22 Accelerator opening degree detection means as accelerator position detection means 27 Shift position detection means

Continuation of front page (56) References JP-A-7-322416 (JP, A) JP-A-50-143962 (JP, A) JP-A-6-315207 (JP, A) (58) Fields studied (Int .Cl. ⁷ , DB name) B60L 15/20 B60L 7/10

Claims (1)

(57) [Claims] 1. A transmission having at least two or more alternately selected shift speeds, an output shaft connected to drive wheels of the vehicle via the transmission, and mounted on the vehicle. An electric motor electrically connected to a battery, a shift position detecting means for detecting a shift speed of the transmission, an operating state detecting means having an accelerator opening detecting means for detecting an accelerator opening, and the above-described shift position detecting means And a torque generated in the electric motor such that a driving force generated in the drive wheels becomes equal before and after performing a shift operation of the transmission at the same accelerator opening, based on each detection information from the accelerator opening detecting means. and a control means for controlling in response to the accelerator opening, the control means, from the shift position detection means and the accelerator opening detection means
Of the target torque of the electric motor based on each detection information of
And a target torque calculated by the calculation unit is generated in the motor.
If the value is larger than the maximum torque that can be
A restricting means for restricting the target torque within the maximum torque.
And the target torque relaxes to the maximum torque in the vicinity of the maximum torque.
Correcting means for correcting the target torque so as to asymptotically approach
An electric vehicle, characterized by having steps .