JPH0993724A - Electric automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To nicely switch the number of speeds of an electric automobile without relying on the skill of the driver of the automobile by controlling the torque generated by a motor in accordance with the opening of the accelerator so that the drive power of driving wheels can become equal to each other before and after the transmission is operated when the opening of the accelerator is constant. SOLUTION: The drive power or brake power of a vehicle outputted through a motor 2, transmission, etc., is set so that the power can become the same regardless of the number of speeds when the opening of the accelerator or brake of the vehicle is constant. That is, the motor torque command value given to the opening of the accelerator or brake when the first gear is engaged is set at: First gear torque command=a×opening of accelerator or brake. The motor torque command value to the opening of the accelerator or brake when the second gear is engaged is set at: Second gear torque command= a×opening of accelerator or brake×(r1×e1)/(r2×e2), where, r1, e1, r2, and r2 represent the first gear ratio, first gear efficiency, second gear ratio, and second gear efficiency, respectively.

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 for traveling, and more particularly to an electric vehicle in which torque control of the motor is improved.

[0002]

2. Description of the Related Art In recent years, electric vehicles have been attracting attention from the viewpoint of preventing air pollution and reducing noise from vehicles. Such an electric vehicle is configured to control the output torque (power running torque) of the motor according to the accelerator opening degree (accelerator depression amount), as in a conventional vehicle such as a gasoline engine. Further, in an electric vehicle, so-called regenerative braking can be easily performed, and for this regenerative braking, the regenerative torque of the motor is controlled according to the brake opening (brake depression amount or brake operating state). .

Although some electric vehicles have a transmission, conventionally, the power running torque of the motor is applied only to the accelerator opening or the brake opening regardless of the selected gear (shift position). Alternatively, the regenerative torque is controlled. For example, FIG. 5 shows characteristics of a power 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 size of the ratio and 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 (r2 × e2) <(r1 × e1) Therefore, the 2nd gear driving force is shown in FIG. As described above, the driving force becomes smaller than the first speed driving force.

The motor torque (power running torque or regenerative torque of the motor) has a characteristic as shown in FIG. 7, and the region where the motor rotation speed is low is a constant torque region where the torque is constant. The high output region is a constant output region where the motor output is constant. In this constant output range,
As shown, the torque decreases as the motor speed increases.

[0007]

However, like the conventional electric vehicle, the motor torque (power running torque or regeneration of the motor) is only related to the accelerator opening or the brake opening regardless of the selected speed. Controlling torque) causes the following problems. 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 changes greatly as shown in FIG. Therefore, if the gear shift operation is performed with the accelerator opening kept constant, the driving force suddenly changes and the driving feeling is deteriorated.

In order to perform a comfortable shift change, it is necessary to make the driving force constant before and after a shift change. For this purpose, the driver appropriately adjusts the amount of depression of the accelerator pedal before and after the shift change. There is a problem that it is necessary to increase the driver's burden on the driving operation.
By the way, for example, Japanese Patent Application Laid-Open No. 6-98420 discloses a technique for improving the switching feeling at the time of switching the shift stage in an electric vehicle. However, this technique is a signal when the shift stage signal is switched. It is related to processing, and such a technique cannot solve the above problems.

The present invention was conceived in view of the above problems, and an object of the present invention is to provide an electric vehicle capable of performing a comfortable gear shift without depending on the driving operation of the driver. .

[0010]

For this reason, the electric vehicle of the present invention according to claim 1 is provided with a transmission having at least two or more selectively selected gears, and via the transmission. An electric motor having an output shaft connected to a drive wheel 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 detection information from the shift position detecting means and the accelerator opening detecting means. Control means for controlling the torque generated in the electric motor according to the accelerator opening so that the driving force generated in the drive wheels becomes equal before and after the gear shift operation of the transmission is performed at the same accelerator opening. It is characterized by having and.

According to a second aspect of the present invention, in the electric vehicle according to the first aspect, the control means uses the electric motor based on the detection information from the shift position detecting means and the accelerator opening detecting means. When the target torque calculated by the calculation unit is larger than the maximum torque that can be generated by the electric motor, the target torque is within the maximum torque. It is characterized in that it has a restricting means to regulate it.

In the electric vehicle of the present invention according to claim 3, in the structure according to claim 2, the target torque is corrected so that the target torque gradually approaches the maximum torque in the vicinity of the maximum torque. It is characterized in that correction means is provided. An electric vehicle according to a fourth aspect of the present invention is the electric vehicle according to the first aspect, wherein the driving state detecting means has a brake operation detecting means for detecting an operating state of the brake, and the control means has the electric motor. The operating state is switched between a powering operation state in which the electric motor drives the drive wheel and a regenerative operation state in which the electric motor regenerates by the rotational force transmitted from the drive wheel, and the electric motor is in the regenerative operation state. In the case of, the driving force generated on the drive wheels before and after performing the gear shifting operation of the transmission at the same accelerator opening based on the detection information from the shift position detecting means and the accelerator opening detecting means. It is characterized in that it is provided with a control means for controlling the torque generated in the electric motor so as to be equal to each other according to the accelerator opening.

According to a fifth aspect of the present invention, in the electric vehicle according to the fourth aspect, the control means uses the electric motor based on the detection information from the shift position detecting means and the accelerator opening detecting means. When the target torque calculated by the calculation unit is larger than the maximum regenerative torque that can be generated in the electric motor, the target torque is calculated as the maximum regenerative torque. It is characterized in that it has a limiting means for regulating the torque within the torque.

According to a sixth aspect of the present invention, in the electric vehicle according to the fifth aspect, the target torque is controlled so that the target torque gradually approaches the maximum regenerative torque in the vicinity of the maximum regenerative torque. It is characterized in that a correction means for correcting is provided.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION 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 structure of the present apparatus will be described. In FIG. 1, reference numeral 1 denotes a battery, and the battery 1 can be repeatedly charged by an external charger not equipped in the vehicle. Reference numeral 2 denotes an electric motor (traveling motor) supplied with electric power from the battery 1, and an output shaft of the motor 2 is provided with drive wheels 4 via a transmission 3.
Are connected. Here, the transmission 3 is a two-speed 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, and the power from the battery 1 is adjusted to a required size and supplied to the motor 2 through the power conversion circuit 5. It has become so. The power conversion circuit 5 is controlled by a motor controller 6. The motor controller 6 controls the output of the motor 2 through the power conversion circuit 5 according to the amount of depression of an accelerator pedal (not shown).

A motor torque control section 7 is provided in the motor controller 6. The motor torque control unit 7 controls the output torque of the motor. For this reason, the motor torque control unit 7 is provided with a storage unit 8, a determination unit 9, a calculation unit 10, and an instruction unit 11. ing. Further, the motor torque control section 7 includes an operating state detecting means 20, that is, a brake opening detecting means 21 as a brake 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 may be performed by controlling the output torque (power running torque) of the motor or by controlling the regenerative torque of the motor. Here, regarding the power running torque command, It is performed according to the accelerator opening (accelerator depression amount) and the selected shift speed, and the regenerative torque command is performed according to the brake opening (brake depression amount) and the selected shift speed. Is configured.

That is, as shown in FIG. 2, basically, the motor torque control is performed so that the motor torque increases in accordance with the increase of the accelerator opening or the brake opening. In a region where the opening 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 the present electric vehicle, if the vehicle driving force or braking force output through the drive system such as the motor 2 and the transmission 3 is constant at the accelerator opening or the brake opening, the shift speed (that is, the first speed). It is set to be constant regardless of whether it is second speed or not.

That is, the driving force or the braking force in the case of the second speed has a relation as shown in the above-mentioned formula (1) with respect to the driving force or the braking force in the case of the first speed, and therefore, the accelerator opening at the first speed is opened. The motor torque command value (power running torque command value or regenerative torque command value) for the degree or the brake opening is set according to 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 basically set based on the command value as shown in Expression (3).

First speed torque command = a × accelerator opening degree or brake opening degree (2) Second speed torque instruction (basic command value) = a × accelerator opening degree or brake opening degree × {(r1 × e1) / (r2 × e2)} (3) where r1: 1 speed gear ratio, e1: 1 speed gear efficiency r2: 2nd speed gear ratio, e2: 2nd speed gear efficiency If the motor torque command value for the second speed is set as described above, the motor torque command value will reach 100% before the accelerator opening or the brake opening is fully opened. Therefore, after that, even if the accelerator opening or the brake opening increases, the motor torque command value becomes 100%.
It is configured to be limited to%.

For this reason, the storage means 8 stores a map or table for calculating the basic command value, and the determination means 9 can determine whether or not the motor torque command value has reached 100%. Has become. Further, the calculating means 10 includes a calculating section 10A for calculating a basic command value and a limiting section (limiter) 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 for the second speed, the rate of increase of the command value suddenly changes when the motor torque command value reaches 100%. Become. Since this may cause a feeling of strangeness, in the present electric vehicle, the motor torque command value is smoothly changed in the vicinity where the motor torque command value reaches 100%, and is set so as to gradually approach 100%. There is.

That is, the accelerator opening or the brake opening θ
However, if 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 θ0), which is 100%, ,
Until the accelerator opening or the brake opening reaches θ0 so as to correspond to the basic command value 100%, the correction amount C1 corresponding 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, the correction amount C2 (= b · Δθ1−b · Δ) according to the increase amount (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, in the vicinity of the motor torque command value reaching 100%, the motor torque command value changes smoothly in a curve and gradually approaches 100%. . Therefore, the determination means 9 is adapted to determine whether or not the motor torque command value has reached this correction range, and the calculation means 10 is corrected by such a calculation process to determine the motor torque command value. A correction unit (correction means) 10C that changes the value smoothly into a curved line is provided.

Since the electric vehicle as one embodiment of the present invention is configured as described above, the torque control of the motor is performed at a predetermined cycle as shown in the flowchart of FIG. 4, for example. That is, the shift position is determined in step S10, and then the torque command value (basic command value) is calculated in accordance with the shift position and the accelerator opening or the brake opening in step S20.

Here, the torque command value (basic command value) is 1
It is determined whether or not it is 00% (maximum command value) or more (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 smoothly changes in the vicinity of the motor torque command value reaching 100% (step S50), and based on the torque command value thus set, Then, the torque command is output from the command means 11.

Thus, in this electric vehicle, the motor 2
And the driving force or braking force of the vehicle output through the drive system such as the transmission 3 is constant regardless of the gear stage (that is, first speed or second speed) if the accelerator opening or the brake opening is constant. Since the motor torque is controlled so that, in the normal region where the accelerator opening or the brake opening is medium or less, if the accelerator opening is constant before and after the shift change,
As shown in FIG. 3, the driving force or the braking force becomes constant before and after the shift change, and the gear shift operation can be performed with a good feeling without a change in the driving force or the braking force.

Therefore, the driver is less burdened to increase / decrease the depression amount of the accelerator pedal before and after the shift change, the driving operation of the driver can be made easier, and the fatigue of the driver due to the driving operation can be reduced. In addition, in the present embodiment, the two-stage transmission is taken as an example, but the present invention is not limited to the shift stage of the transmission. Therefore, if the motor torque command value for the accelerator opening or the brake opening at the 2nd 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 becomes The command value as in (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 High speed gear ratio, e1: 1st speed gear efficiency rn: nth speed gear ratio, en: nth speed gear efficiency Of course, also in this case, if the basic command value reaches 100%, the accelerator opening or the brake opening increases. The torque command value is limited to 100%. Also, the torque command value is 1
It is desirable that the torque command value be gradually approached to 100% so that the torque command value can be smoothly transferred when transitioning to 00%.

Further, 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. Alternatively, 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.
It is set so as to have the characteristics shown in.

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

[0033]

As described above in detail, according to the electric vehicle of the present invention as set forth in claim 1, there is provided a transmission having at least two or more selectively selected gears, and the transmission. An output shaft is connected to the drive wheels of the vehicle via an electric motor electrically connected to a battery mounted on the vehicle, a shift position detecting means for detecting a shift stage of the transmission, and an accelerator opening degree. Based on the operating state detecting means having the accelerator opening detecting means for detecting, and the detection information from the shift position detecting means and the accelerator opening detecting means, before and after performing the shift operation of the transmission at the same accelerator opening. And a control means for controlling the torque generated in the electric motor according to the accelerator opening so that the driving force generated in the drive wheels becomes 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 a second aspect of the present invention, in the configuration of the first aspect, the control means is based on each detection information from the shift position detecting means and the accelerator opening detecting means. A calculation unit that calculates the magnitude of the target torque of the electric motor, and if the target torque calculated by the calculation unit is a value that is larger than the maximum torque that can be generated in the electric motor, the target torque is set to the maximum value. Due to the configuration including the limiting means for restricting the torque within the torque, the torque is set within the controllable range during power running, and smooth torque control is realized.

According to the electric vehicle of the present invention described in claim 3, in the configuration of claim 2, the target torque is controlled so that the target torque gradually approaches the maximum torque in the vicinity of the maximum torque. With the configuration in which the correction means for correcting is provided, the output is adjusted more smoothly during power running, and the riding comfort is improved. According to the electric vehicle of the present invention described in claim 4, in the configuration described in claim 1, the driving state detecting means has a brake operation detecting means for detecting an operating state of the brake, and the control means includes: The operating state of the electric motor is switched between a powering operating state in which the electric motor drives the drive wheels and a regenerative operating state in which the electric motor regenerates by the rotational force transmitted from the drive wheels,
When the electric motor is in the regenerative operation state, the drive is performed before and after performing the speed change operation of the transmission at the same accelerator opening based on the detection information from the shift position detecting means and the accelerator opening detecting means. With a configuration that includes a control means that controls the torque generated in the electric motor according to the accelerator opening so that the driving force generated in the wheels becomes equal, the accelerator operation load on the driver before and after the shift change is reduced, At the time of regeneration, it is possible to realize a smooth and comfortable shift of the shift speed while facilitating the driving operation of the driver.

According to a fifth aspect of the present invention, in the electric vehicle according to the fourth aspect, the control means is based on each detection information from the shift position detecting means and the accelerator opening detecting means. A calculation unit that calculates the magnitude of the target torque of the electric motor, and if the target torque calculated by the calculation unit is a value that is larger than the maximum regenerative torque that can be generated in the electric motor, Due to the configuration with limiting means that regulates within the maximum regenerative torque, the torque is set within the controllable range during regeneration,
Smooth torque control is realized.

According to the electric vehicle of the present invention described in claim 6, in the structure described in claim 5, the target torque is gradually approached to the maximum regenerative torque in the vicinity of the maximum regenerative torque. With the configuration in which the correction means for correcting the torque is provided, the output is adjusted more smoothly during regeneration and the riding comfort is improved.

[Brief description of drawings]

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

FIG. 2 is a diagram showing 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 according to an embodiment of the present invention.

FIG. 4 is a flowchart showing motor control by an electric vehicle according to an 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 motor torque setting characteristic of a conventional electric vehicle.

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

[Explanation of symbols]

1 Battery 2 Electric Motor (Running Motor) 3 Transmission 4 Drive Wheel 5 Power Conversion Circuit 6 Motor Controller 7 Motor Torque Control Section (Control Means) 8 Storage Means 9 Judgment Means 10 Calculating Means 10A Calculating Means 10B Limiting Means (Limiting Means) 10C Correcting unit (correcting means) 11 Instructing means 20 Operating state detecting means 21 Brake opening detecting means as brake operation detecting means 22 Accelerator opening detecting means as accelerator position detecting means 27 Shift position detecting means

Claims (6)

[Claims] 1. A transmission having at least two or more selectively selected gears, and an output shaft connected to the drive wheels of the vehicle via the transmission and mounted on the vehicle. An electric motor electrically connected to the battery, an operating state detecting means having a shift position detecting means for detecting a shift stage of the transmission and an accelerator opening detecting means for detecting an accelerator opening, and the above shift position detecting means. And the torque generated in the electric motor so that the driving force generated in the drive wheels becomes equal before and after the gear shift operation of the transmission is performed at the same accelerator opening based on each detection information from the accelerator opening detection means. An electric vehicle comprising: a control unit that controls according to the accelerator opening. 2. The calculation means for calculating the magnitude of the target torque of the electric motor based on the detection information from the shift position detection means and the accelerator opening detection means, and the calculation means. A limiting means for restricting the target torque to be within the maximum torque when the set target torque is larger than the maximum torque that can be generated in the electric motor. The electric vehicle according to 1. 3. A correction means for correcting the target torque is provided so that the target torque gradually approaches the maximum torque in the vicinity of the maximum torque.
The electric vehicle according to claim 2. 4. The driving state detecting means includes a brake operation detecting means for detecting an operating state of the brake, and the control means controls an operating state of the electric motor to drive the driving wheel by the electric motor. While switching between an operating state and a regenerative operating state in which the electric motor regenerates by the rotational force transmitted from the drive wheels, when the electric motor is in the regenerative operating state, the shift position detecting means and the accelerator opening Based on each detection information from the detection means, the torque generated in the electric motor is set to a torque generated in the electric motor so that the driving force generated in the drive wheels becomes equal before and after the gear shift operation of the transmission is performed at the same accelerator opening. The electric vehicle according to claim 1, further comprising: a control unit that controls the electric vehicle according to. 5. The control means calculates a magnitude of a target torque of the electric motor on the basis of each detection information from the shift position detection means and the accelerator opening detection means, and the calculation section. When the set target torque is a value larger than the maximum regenerative torque that can be generated in the electric motor, the target torque is limited to within the maximum regenerative torque. Claim 4
The electric vehicle described. 6. The correction means for correcting the target torque is provided so that the target torque gradually approaches the maximum regenerative torque in the vicinity of the maximum regenerative torque. The electric vehicle described.