JP6374705B2 - Automobile - Google Patents

Description

  The present invention relates to an automobile in which wheels are driven only by a motor.

  Conventionally, for example, a four-wheel drive vehicle has been proposed in which the right front wheel and the left front wheel are driven by a front motor and an engine, the right rear wheel is driven by a rear right motor, and the left rear wheel is driven by a rear left motor. (See Patent Document 1).

  In such an automobile, the driving force to be transmitted to the right front wheel and the left front wheel (front driving force), the driving force to be transmitted to the right rear wheel (rear right driving force) so as to keep the motor efficiency above a predetermined value, The driving force distribution of the driving force (rear left driving force) to be transmitted to the left rear wheel is determined.

JP 2007-313982 A

  By the way, in such an automobile, for example, at the time of turning, a driving force difference is provided between the rear right driving force and the rear left driving force to generate a yaw rate, thereby improving the turning performance. However, in the driving force distribution that keeps the motor efficiency of each motor at a predetermined value or more, there is a problem that a required driving force difference required for the rear right driving force and the rear left driving force cannot be generated. there were.

  Accordingly, an object of the present invention is to provide an automobile capable of suppressing power consumption while ensuring a required driving force difference between left and right wheels.

  In order to solve the above problems, an automobile according to the present invention provides a first motor for driving a first right wheel, a second motor for driving a first left wheel, the first right wheel, and the first left wheel. A third motor for driving a second right wheel and a second left wheel provided in front or rear, and a controller for controlling the driving of the first motor, the second motor, and the third motor, and the control A first requested driving force to be transmitted to the first right wheel, a second requested driving force to be transmitted to the first left wheel, and a third to be transmitted to the second right wheel and the second left wheel. A required driving force deriving unit for deriving a total required driving force which is a sum of the required driving forces and deriving a driving force difference between the first required driving force and the second required driving force; and the first required driving force and In the state where it is assumed that there is no driving force difference in the second required driving force, Distributing the driving force between the first required driving force and the sum of the second required driving force and the third required driving force so that the total power consumption of the motor, the second motor, and the third motor is minimized. And the first required driving force, the second required driving force, and the third required driving force of the first candidate are derived based on the driving force distribution, the driving force difference, and the total required driving force. In addition, based on the driving force difference and the total required driving force so that one of the first required driving force and the second required driving force is 0, the first required driving force of the second candidate A candidate driving force deriving unit for deriving the second required driving force and the third required driving force, and the first motor when the first right wheel is driven with the first candidate driving force of the first candidate. Before power consumption, when the first left wheel is driven with the second required driving force of the first candidate The sum of the power consumption of the second motor and the sum of the power consumption of the third motor when the second right wheel and the second left wheel are driven with the third candidate driving force of the first candidate is consumed by the first candidate It is derived as electric power, and when the first right wheel is driven by the first candidate driving force of the second candidate, the power consumption of the first motor, and the first candidate by the second candidate driving force of the second candidate The power consumption of the second motor when the left wheel is driven, and the power consumption of the third motor when the second right wheel and the second left wheel are driven with the third candidate driving force of the second candidate A power consumption deriving unit for deriving the sum as power consumption of the second candidate, and selecting a candidate with low power consumption among the first candidate and the second candidate, and using the first required driving force corresponding to the selected candidate The first motor is driven to drive the first right wheel and corresponds to the selected candidate. The second motor is driven to drive the first left wheel with the second required driving force, and the second right wheel and the second left wheel are driven with the third required driving force corresponding to the selected candidate. And a drive control unit for driving the third motor.

  Further, the candidate driving force deriving unit is configured such that one of the first required driving force and the second required driving force is a maximum driving force that the corresponding first motor or the second motor can output at a current vehicle speed. Based on the vehicle speed, the driving force difference, and the total required driving force, the first required driving force, the second required driving force, and the third required driving force of a third candidate are derived, The power consumption deriving unit consumes power of the first motor when the first right wheel is driven by the first required driving force of the third candidate, and the second required driving force of the third candidate Power consumption of the second motor when driving one left wheel, and power consumption of the third motor when driving the second right wheel and the second left wheel with the third candidate driving force of the third candidate Deriving the sum of power as the power consumption of the third candidate, Control unit, the first candidate, the power consumption of the second candidate and the third candidate may be selected the lowest candidates.

  Further, the automobile of the present invention is provided in front of or behind the first motor for driving the first right wheel, the second motor for driving the first left wheel, and the first right wheel and the first left wheel. A third motor that drives the second right wheel and the second left wheel; and a control unit that controls driving of the first motor, the second motor, and the third motor, wherein the control unit includes the first motor The sum of the first required driving force to be transmitted to the right wheel, the second required driving force to be transmitted to the first left wheel, and the third required driving force to be transmitted to the second right wheel and the second left wheel. A required driving force deriving unit that derives a total required driving force and derives a driving force difference between the first required driving force and the second required driving force; and the first required driving force and the second required driving force. On the assumption that there is no difference in driving force between the first motor and the second motor. And determining the driving force distribution between the first required driving force and the sum of the second required driving force and the third required driving force so that the total power consumption of the motor and the third motor is minimized. Deriving the first required driving force, the second required driving force and the third required driving force of a first candidate based on the driving force distribution, the driving force difference and the total required driving force; The vehicle speed, the driving force so that one of the first required driving force and the second required driving force is the maximum driving force that the corresponding first motor or the second motor can output at the current vehicle speed. Based on the difference and the total required driving force, a candidate driving force deriving unit for deriving the first required driving force, the second required driving force, and the third required driving force of a third candidate; The first motor when the first right wheel is driven with the first required driving force Power consumption, power consumption of the second motor when the first left wheel is driven with the second candidate driving force of the first candidate, and the second right wheel with the third candidate driving force of the first candidate The sum of power consumption of the third motor when the second left wheel is driven is derived as power consumption of the first candidate, and the first right wheel is driven with the first required driving force of the third candidate. Power consumption of the first motor in this case, power consumption of the second motor when driving the first left wheel with the second required driving force of the third candidate, and the third required driving force of the third candidate A power consumption deriving unit for deriving a sum of power consumptions of the third motor when the second right wheel and the second left wheel are driven as a third candidate power consumption, and the first candidate and the third candidate A candidate with low power consumption is selected, and the first required driving force corresponding to the selected candidate is The first motor is driven so as to drive the first right wheel, and the second motor is driven so as to drive the first left wheel with the second required driving force corresponding to the selected candidate. A drive control unit that drives the third motor so as to drive the second right wheel and the second left wheel with the third required driving force corresponding to the candidate.

  According to the present invention, it is possible to suppress power consumption while ensuring a required driving force difference between left and right wheels.

It is a figure which shows the structure of a motor vehicle. It is a figure which shows the motor efficiency map of a rear right motor and a rear left motor. It is a flowchart (1) explaining the flow of the drive control processing. It is a flowchart (2) explaining the flow of the drive control process. It is a figure which shows the simulation result of system efficiency.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiments are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. To do.

  FIG. 1 is a diagram illustrating a configuration of the automobile 100. As shown in FIG. 1, the automobile 100 is provided with a front motor 102, a rear right motor 104, and a rear left motor 106. In the automobile 100, the front front wheel 102 drives the right front wheel 110 and the left front wheel 112, the rear right motor 104 drives the right rear wheel 114, and the rear left motor 106 drives the left rear wheel 116. To drive.

  The front motor 102 is connected to the right front wheel 110 and the left front wheel 112 via a gear mechanism 120 and a front output shaft 122. The front motor 102 is connected to the battery 150 via the inverter 124, and is rotationally driven by the electric power supplied from the battery 150. The power obtained by the rotational drive is transmitted via the gear mechanism 120 and the front output shaft 122. This is transmitted to the right front wheel 110 and the left front wheel 112. The front motor 102 also functions as a generator at a timing different from the power transmission, generates electric power based on the rotation of the right front wheel 110 and the left front wheel 112, and stores the electric power obtained by the power generation in the battery 150.

  The rear right motor 104 is connected to the right rear wheel 114 via a gear mechanism 130 and a rear right output shaft 132. The rear right motor 104 is connected to the battery 150 via the inverter 134, and is driven to rotate by the electric power supplied from the battery 150. The power obtained by the rotation driving is transmitted to the gear mechanism 130 and the rear right output shaft 132. To the right rear wheel 114. Further, the rear right motor 104 also functions as a generator at a timing different from the power transmission, generates electric power based on the rotation of the right rear wheel 114, and stores electric power obtained by the electric power generation in the battery 150.

  The rear left motor 106 is connected to the left rear wheel 116 via a gear mechanism 140 and a rear left output shaft 142. The rear left motor 106 is electrically connected to the battery 150 via the inverter 144, and is rotationally driven by the electric power supplied from the battery 150. The power obtained by the rotational drive is output to the gear mechanism 140 and the rear left output. This is transmitted to the left rear wheel 116 via the shaft 142. The rear left motor 106 also functions as a generator at a timing different from the power transmission, generates electric power based on the rotation of the left rear wheel 116, and stores electric power obtained by the electric power generation in the battery 150.

  The battery 150 is connected to a battery control unit (hereinafter also referred to as BCU) 152 and controlled by the BCU 152. The BCU 152 is connected to the control unit 160, monitors the charge / discharge current amount, temperature, and the like of the battery 150, calculates the remaining capacity of the battery 150 based on the charge / discharge current amount, and obtains data related to the battery 150 as necessary. To the control unit 160.

  The control unit 160 is a microcomputer including a CPU (Central Processing Unit), a RAM (Random Access Memory), and a ROM (Read Only Memory), and comprehensively controls each unit. The control unit 160 is connected to a rotation speed sensor 162, 164, 166, an accelerator pedal sensor 168, a brake pedal sensor 170, a handle sensor 172, a vehicle speed sensor 174, and an acceleration sensor 176, and is detected by each sensor (162 to 176). A signal indicating the measured value is input. The control unit 160 is connected to the inverters 124, 134, and 144, and based on signals input from the sensors (162 to 176), the front motor 102 and the rear right motor 104 are connected via the inverters 124, 134, and 144. Further, the driving or power generation of the rear left motor 106 is controlled.

  The rotation speed sensors 162, 164, and 166 are, for example, resolvers, detect the rotation speeds of the front motor 102, the rear right motor 104, and the rear left motor 106, respectively, and output a signal indicating the rotation speed to the control unit 160.

  The accelerator pedal sensor 168 detects an accelerator pedal depression amount (accelerator depression amount) and outputs a signal indicating the accelerator depression amount to the control unit 160. The brake pedal sensor 170 detects the depression amount (brake depression amount) of the brake pedal, and outputs a signal indicating the brake depression amount to the control unit 160. The handle sensor 172 detects the rotation angle (steering angle) of the handle and outputs a signal indicating the rotation angle to the control unit 160.

  The vehicle speed sensor 174 detects the vehicle speed of the automobile 100 and outputs a signal indicating the vehicle speed to the control unit 160. The acceleration sensor 176 detects the acceleration of the automobile 100 and outputs a signal indicating the acceleration to the control unit 160.

  Here, in the conventional automobile, the driving force to be transmitted to the right front wheel and the left front wheel (front driving force, third required driving force) and the driving to be transmitted to the right rear wheel so that the motor efficiency is maintained at a predetermined value or more. The driving force distribution of the force (rear right driving force, first required driving force) and the driving force to be transmitted to the left rear wheel (rear left driving force, second required driving force) is determined. . For example, during turning, a difference in driving force is provided between the rear right driving force and the rear left driving force to generate a yaw rate to improve turning performance. However, the motor efficiency of each motor is maintained at a predetermined value or more. In such a driving force distribution, there is a problem that a required driving force difference required for the rear right driving force and the rear left driving force cannot be generated.

  Therefore, the control unit 160 derives power consumption PEn (n = 1 to 3) for the front motor 102, the rear right motor 104, and the rear left motor 106 in three candidates, which will be described in detail later. The candidate with the smallest power consumption PEn is selected. Then, the control unit 160 controls the front motor 102, the rear right motor 104, and the rear left motor 106 under conditions corresponding to the selected candidate. The reason why the second candidate and the third candidate are provided in addition to the first candidate will be described later. Further, the symbol n = 1 represents the first candidate, n = 2 represents the second candidate, and n = 3 represents the third candidate.

  Hereinafter, the control unit 160 derives the power consumption PEn of the first candidate to the third candidate, and based on the derived power consumption PEn of the first candidate to the third candidate, the front motor 102, the rear right motor 104, A drive control process for controlling the rear left motor 106 will be described. As illustrated in FIG. 1, the control unit 160 performs a drive control process as a signal acquisition unit 200, a required driving force deriving unit 202, a candidate driving force deriving unit 204, a power consumption deriving unit 206, and a driving control unit 208. Function.

  The signal acquisition unit 200 acquires signals from the rotation speed sensors 162, 164, 166, the accelerator pedal sensor 168, the brake pedal sensor 170, the handle sensor 172, the vehicle speed sensor 174, and the acceleration sensor 176 at predetermined intervals.

  Based on the accelerator pedal depression amount acquired from the accelerator pedal sensor 168 and the vehicle speed V acquired from the vehicle speed sensor 174, the required driving force deriving unit 202 refers to a required driving force map stored in advance in the ROM, A required driving force (total required driving force) FT for the entire automobile 100 is determined. Further, the required driving force deriving unit 202 refers to the required driving force difference map stored in advance in the ROM based on the vehicle speed V and the rotation angle acquired from the handle sensor 172, so that the rear right driving force FRRn (n : 1 to 3) and the required driving force difference DR between the rear left driving force FRLn (n: 1 to 3) is determined.

The candidate driving force deriving unit 204 derives the first candidate front driving force FF1, rear right driving force FRR1, and rear left driving force FRL1. Specifically, the candidate driving force deriving unit 204 refers to the front and rear wheel driving force maps stored in advance in the ROM based on the vehicle speed V and the required driving force FT, and the front driving force FF1 and the rear driving force (rear) The sum of the right driving force FRR1 and the rear left driving force FRL1) FR1 is determined. Then, the candidate driving force deriving unit 204 derives the front driving force FF1 and the rear driving force FR1 based on the determined driving force distribution and the required driving force FT. Subsequently, the candidate driving force deriving unit 204 derives the rear right driving force FRR1 and the rear left driving force FRL1 by substituting the required driving force difference DR and the rear driving force FR1 into the following equations (1) and (2). To do.
FRR1 = (FR1 + DR) / 2 (1)
FRL1 = (FR1-DR) / 2 (2)

  Next, the candidate driving force deriving unit 204 derives the second candidate front driving force FF2, rear right driving force FRR2, and rear left driving force FRL2. Specifically, the candidate driving force deriving unit 204 is one of the rear right driving force FRR2 and the rear left driving force FRL2 whose driving force should be relatively reduced based on the rotation angle acquired from the handle sensor 172. The driving force is 0. For example, when the automobile 100 turns right, the rear right driving force FRR2 = 0, and when the automobile 100 turns left, the rear left driving force FRL2 = 0.

When the rear left driving force FRL2 = 0, the candidate driving force deriving unit 204 substitutes the required driving force difference DR and the required driving force FT into the following equations (3) and (4), and the rear right driving force FRL2 = 0. A driving force FRR2 and a front driving force FF2 are derived.
FRR2 = DR (3)
FF2 = FT-DR (4)

Further, when the rear right driving force FRR2 = 0, the candidate driving force deriving unit 204 substitutes the required driving force difference DR and the required driving force FT into the following equations (5) and (6), and the rear left driving force FRR2 = 0. The driving force FRL2 and the front driving force FF2 are derived.
FRL2 = DR (5)
FF2 = FT-DR (6)

  Next, the candidate driving force deriving unit 204 derives the third candidate front driving force FF3, rear right driving force FRR3, and rear left driving force FRL3. Specifically, the candidate driving force deriving unit 204 determines, based on the rotation angle acquired from the handle sensor 172, one of the rear right driving force FRR3 and the rear left driving force FRL3 that should have a relatively large driving force. decide.

Then, when the candidate driving force deriving unit 204 determines to make the rear right driving force FRR3 larger than the rear left driving force FRL3, the candidate right driving force FRR3 is associated with the motor characteristics of the rear right motor 104 based on the vehicle speed V. With reference to the maximum driving force map, the rear right maximum driving force FRRmax that can be output by the rear right motor 104 at the current vehicle speed V is derived as the rear right driving force FRR3. The candidate driving force deriving unit 204 substitutes the required driving force difference DR and the required driving force FT into the following equations (7) and (8) to derive the rear left driving force FRL3 and the front driving force FF3. .
FRL3 = FRR3-DR (7)
FF3 = FT− (FRR3 + FRL3) (8)

On the other hand, when the candidate driving force deriving unit 204 determines that the rear left driving force FRL3 is larger than the rear right driving force FRR3, the rear left driving force FRL3 is associated with the motor characteristics of the rear left motor 106 based on the vehicle speed V. With reference to the maximum driving force map, the rear left maximum driving force FRLmax that can be output by the rear left motor 106 at the current vehicle speed V is derived as the rear left driving force FRL3. Further, the candidate driving force deriving unit 204 derives the rear right driving force FRR3 and the front driving force FF3 by substituting the required driving force difference DR and the required driving force FT into the following equations (9) and (10). .
FRR3 = FRL3-DR (9)
FF3 = FT− (FRR3 + FRL3) (10)

The power consumption deriving unit 206 includes torques (front motor torque) TMFn (n: 1 to 3) of the first to third candidate front motors 102, torque (rear right motor torque) TMRRn (n: 1 to 3) and the torque of the rear left motor 106 (rear left motor torque) TMRLn (n: 1 to 3) are derived. Specifically, the power consumption deriving unit 206 substitutes the front driving force FFn, the tire radius TR, and the rotational speed (front motor rotational speed) NMF of the front motor 102 acquired from the rotational speed sensor 162 into the following equation (11). To derive the front motor torque TMFn.
TMFn = FFn × TR / NMF (11)

Further, the power consumption deriving unit 206 substitutes the rear right driving force FRRn, the tire radius TR, and the rotational speed (rear right motor rotational speed) NMRR of the rear right motor 104 acquired from the rotational speed sensor 164 into the following equation (12). To derive the rear right motor torque TMRRn.
TMRRn = FRRn × TR / NMRR (12)

Further, the power consumption deriving unit 206 substitutes the rear left driving force FRLn, the tire radius TR, and the rotation number (rear left motor rotation number) NMRL of the rear left motor 106 acquired from the rotation number sensor 166 into the following equation (13). The rear left motor torque TMRLn is derived.
TMRLn = FRLn × TR / NMRL (13)

  Next, the power consumption deriving unit 206 performs motor efficiency (front motor efficiency) kMFn (n: 1 to 3) of the first to third candidate front motors 102, and motor efficiency (rear right motor efficiency) of the rear right motor 104. ) KMRRn (n: 1 to 3) and motor efficiency (rear left motor efficiency) kMRLn (n: 1 to 3) of the rear left motor 106 are derived. Specifically, the power consumption deriving unit 206 derives the front motor efficiency kMFn with reference to the front motor efficiency map stored in advance in the ROM based on the front motor rotation speed NMF and the front motor torque TMFn. The candidate driving force deriving unit 204 derives the rear right motor efficiency kMRRn by referring to the rear right motor efficiency map stored in advance in the ROM based on the rear right motor rotational speed NMRR and the rear right motor torque TMRRn. . The candidate driving force deriving unit 204 derives the rear left motor efficiency kMRLn by referring to the rear left motor efficiency map stored in advance in the ROM based on the rear left motor rotation speed NMRL and the rear left motor torque TMRLn. .

Then, the power consumption deriving unit 206 derives the first to third candidate power consumption PEn (n: 1 to 3) using the following equation (14).
PEn = TMFn × NMF / kMF / 1000
+ TMRRn × NMRR / kMRR / 1000
+ TMRLn × NMRL / kMRL / 1000 (14)

  The drive control unit 208 selects any one of the first to third candidate power consumptions PEn derived by the candidate driving force deriving unit 204 and taking the minimum value. Then, the drive control unit 208 drives the front motor 102 with the front motor torque TMFn of any one of the selected first to third candidates. Further, the drive control unit 208 drives the rear right motor 104 with the rear right motor torque TMRRn of any one of the selected first to third candidates. Further, the drive control unit 208 drives the rear left motor 106 with the rear left motor torque TMRLn of any one of the selected first to third candidates.

  Thus, the first candidate assumes that there is no difference in driving force between the rear right driving force and the rear left driving force, and the front driving force FF1 and the rear driving force are such that the power consumption of the entire motor is minimized. A driving force distribution with the driving force FR1 is derived. Then, based on the determined driving force distribution and the requested driving force FT, the front driving force FF1, the rear right driving force FRR1, and the rear left driving force FRL1 are derived, and the power consumption PE1 is derived. Accordingly, when there is no driving force difference between the rear right driving force FRR1 and the rear left driving force FRL1, or when the driving force difference between the rear right driving force FRR1 and the rear left driving force FRL1 is small, the first candidate to The power consumption PE1 is the smallest among the third candidate power consumptions PEn.

  On the other hand, for example, at the time of turning, the required driving force difference DR is provided between the rear right driving force and the rear left driving force to generate the yaw rate, and the turning performance is improved. Since the first candidate assumes that there is no difference in driving force between the rear right driving force and the rear left driving force, the power consumption PE1 in the entire motor increases. In particular, when the rear right driving force FRR1 or the rear left driving force FRL1 becomes a negative driving force (braking force), the other motors must be driven by the driving force to which the corresponding driving force is added. This further increases the power consumption PE1. Therefore, in the present embodiment, a second candidate and a third candidate are provided for the first candidate.

  As the second candidate, the power consumption PE2 is derived when one of the rear right driving force FRR2 and the rear left driving force FRL2 is zero. When turning, a difference in driving force is provided between the rear right driving force and the rear left driving force. By setting one of the rear right driving force FRR2 and the rear left driving force FRL2 to 0, the required driving force difference DR is reduced. While securing, it is possible to prevent a negative driving force (braking force) during turning or the like and to suppress power consumption.

  The third candidate is that one of the rear right driving force FRR3 and the rear left driving force FRL3 is set to the motor maximum driving force FRRmax or FRLmax, so that the power consumption is reduced when the driving force distribution of the rear driving force is increased. In this case, it is possible to suppress power consumption as compared with other candidates while ensuring the required driving force difference DR.

  FIG. 2 is a diagram showing motor efficiency maps of the rear right motor 104 and the rear left motor 106. As shown in FIG. 2, when the rear right motor 104 and the rear left motor 106 are driven at the maximum torque within a certain rotational speed range, the motor efficiency becomes maximum. Therefore, the third candidate can be said to be a candidate that can reduce the power consumption of the entire motor by driving one of the rear right motor 104 and the rear left motor 106 with the maximum torque (maximum driving force).

  Therefore, the control unit 160 derives the power consumption PEn of the first candidate to the third candidate, selects the candidate with the lowest power consumption, and controls the front motor 102, the rear right motor 104, and the rear left motor 106. Thus, it is possible to suppress power consumption while ensuring the required driving force difference DR. This is particularly effective when the required driving force difference DR must be continuously generated by the crosswind.

  3 and 4 are flowcharts illustrating the flow of the drive control process. As shown in FIG. 3, when the drive control process is started, the signal acquisition unit 200 includes the rotation speed sensors 162, 164, 166, the accelerator pedal sensor 168, the brake pedal sensor 170, the handle sensor 172, the vehicle speed sensor 174, and the acceleration sensor 176. A signal is acquired from (S100).

  The required driving force deriving unit 202 determines the required driving force FT for the entire automobile 100 with reference to the required driving force map based on the depression amount of the accelerator pedal and the vehicle speed V. Further, the required driving force deriving unit 202 determines the required driving force difference DR with reference to the required driving force difference map based on the vehicle speed V and the rotation angle (S102).

  The candidate driving force deriving unit 204 determines the driving force distribution between the front driving force FF1 and the rear driving force FR1 with reference to the front and rear wheel driving force map based on the vehicle speed V and the required driving force FT. The candidate driving force deriving unit 204 derives the front driving force FF1 and the rear driving force FR1 based on the driving force distribution and the required driving force FT, and uses the above equations (1) and (2) to The right driving force FRR1 and the rear left driving force FRL1 are derived (S104).

  Next, the candidate driving force deriving unit 204 sets one of the rear right driving force FRR2 and the rear left driving force FRL2 as a driving force that should be relatively reduced. The candidate driving force deriving unit 204 derives the rear right driving force FRR2 and the front driving force FF2 using the above equations (3) and (4) when the rear left driving force FRL2 = 0. When the right driving force FRR2 = 0, the rear left driving force FRL2 and the front driving force FF2 are derived using the above equations (5) and (6) (S106).

  Next, the candidate driving force deriving unit 204 determines one of the rear right driving force FRR3 and the rear left driving force FRL3 that should have a relatively large driving force. When the candidate driving force deriving unit 204 determines to make the rear right driving force FRR3 larger than the rear left driving force FRL3, the candidate driving force deriving unit 204 refers to the rear right maximum driving force map based on the vehicle speed V, and determines the current vehicle speed V The rear right maximum driving force FRRmax that the rear right motor 104 can output is derived as the rear right driving force FRR3. The candidate driving force deriving unit 204 derives the rear right driving force FRR3 and the front driving force FF3 using the above equations (7) and (8) (S108).

  In addition, when the candidate driving force deriving unit 204 determines to make the rear left driving force FRL3 larger than the rear right driving force FRR3, the candidate driving force deriving unit 204 refers to the rear left maximum driving force map based on the vehicle speed V, and determines the current vehicle speed V The rear left maximum driving force FRLmax that can be output by the rear left motor 106 is derived as the rear left driving force FRL3. Further, the candidate driving force deriving unit 204 derives the rear right driving force FRR3 and the front driving force FF3 using the above equations (9) and (10) (S108).

  The power consumption deriving unit 206 derives the first candidate front motor torque TMF1, rear right motor torque TMRR1, and rear left motor torque TMRL1 using the above equations (11), (12), and (13) ( S110).

  Further, the power consumption deriving unit 206 derives the second candidate front motor torque TMF2, rear right motor torque TMRR2, and rear left motor torque TMRL2 using the above equations (11), (12), and (13). (S112).

  Further, the power consumption deriving unit 206 derives the third candidate front motor torque TMF3, rear right motor torque TMRR3, and rear left motor torque TMRL3 using the above equations (11), (12), and (13). (S114).

  Next, the power consumption deriving unit 206 displays the first candidate front motor efficiency kMF1, rear right motor efficiency kMRR1 and rear left motor efficiency kMRL1, a front motor efficiency map, a rear right motor efficiency map, and a rear left motor efficiency map, respectively. Derived by referring to (S116).

  Further, the power consumption deriving unit 206 refers to the front motor efficiency map, the rear right motor efficiency map, and the rear left motor efficiency map for the second candidate front motor efficiency kMF2, the rear right motor efficiency kMRR2, and the rear left motor efficiency kMRL2. Is derived (S118).

  Also, the power consumption deriving unit 206 refers to the third candidate front motor efficiency kMF3, rear right motor efficiency kMRR3, and rear left motor efficiency kMRL3, respectively, the front motor efficiency map, the rear right motor efficiency map, and the rear left motor efficiency map. Is derived (S120).

  Next, the power consumption deriving unit 206 derives the first candidate power consumption PE1 using the above equation (14) (S122), and the second candidate power consumption PE2 using the above equation (14). Derived (S124), and the third candidate power consumption PE3 is derived using the above equation (14) (S126).

  Subsequently, as illustrated in FIG. 4, the drive control unit 208 determines whether or not the first candidate power consumption PE1 of the first to third candidate power consumption PEn is the minimum value (S128). If power consumption PE1 of the first candidate is the minimum value (YES in S128), drive control unit 208 uses front motor 102, rear right with front motor torque TMF1, rear right motor torque TMRR1, and rear left motor torque TMRL1. The motor 104 and the rear left motor 106 are each driven (S130).

  If the power consumption PE1 of the first candidate is not the minimum value (NO in S128), the drive control unit 208 determines that the power consumption PE2 of the second candidate among the power consumption PEn of the first candidate to the third candidate is the minimum value. It is determined whether or not there is (S132). If power consumption PE2 of the second candidate is the minimum value (YES in S132), drive control unit 208 uses front motor 102, rear right with front motor torque TMF2, rear right motor torque TMRR2, and rear left motor torque TMRL2. The motor 104 and the rear left motor 106 are each driven (S134).

  On the other hand, if the power consumption PE2 of the second candidate is not the minimum value (NO in S132), that is, the power consumption PE3 of the third candidate among the power consumption PEn of the first candidate to the third candidate is the minimum value. In this case, the drive control unit 208 drives the front motor 102, the rear right motor 104, and the rear left motor 106 with the front motor torque TMF3, the rear right motor torque TMRR3, and the rear left motor torque TMRL3, respectively (S136). The process ends.

  FIG. 5 is a diagram showing a simulation result of system efficiency. FIG. 5A shows the front output (front) when the vehicle speed V is 40 km / h, the required output (corresponding to the required driving force) is 20 kW, and the required output difference (corresponding to the required driving force difference) is 2 kW. Equivalent to driving force), rear right output (equivalent to rear right driving force), rear left output (equivalent to rear left driving force), front output loss, rear right output loss, rear left output loss and total loss (in terms of power consumption) It is the simulation result which calculated (equivalent). Note that the front / rear driving force distribution in the state where the driving force difference is assumed to be 0 in the first candidate is 1: 1. The same applies to FIGS. 5B, 5C, and 5D.

  FIG. 5B shows the front output, rear right output, rear left output, front output loss, rear right when the vehicle speed V is 40 km / h, the required output is 20 kW, and the required output difference is 4 kW. It is the simulation result which computed output loss, rear left output loss, and total loss.

  FIG. 5 (c) shows the front output, the rear right output, the rear left output, the front output loss, the rear right when the vehicle speed V is 40 km / h, the required output is 28 kW, and the required output difference is 2 kW. It is the simulation result which computed output loss, rear left output loss, and total loss.

  FIG. 5D shows the front output, rear right output, rear left output, front output loss, rear right when the vehicle speed V is 40 km / h, the required output is 28 kW, and the required output difference is 4 kW. It is the simulation result which computed output loss, rear left output loss, and total loss.

  As shown in FIGS. 5A and 5C, when the required output difference is 2 kW, the total loss of the first candidate is the smallest, so that the power consumption of the first candidate is the smallest. As shown in FIGS. 5A and 5B, when the required output is 20 kW and the required output difference is 4 kW, which is larger than 2 kW, the required output difference is 2 kW compared to the case where the required output difference is 2 kW. It can also be seen that the total loss of the first candidate is increased and the total loss of the second candidate and the third candidate is decreased. And when a request | requirement output difference is 4 kW, since the total loss of a 2nd candidate is the smallest, it turns out that the power consumption of a 2nd candidate becomes the smallest.

  As shown in FIGS. 5C and 5D, when the required output is 28 kW, which is larger than 20 kW, and the required output difference is 4 kW, which is larger than 2 kW, the required output is the same as that of 20 kW. It can also be seen that the total loss of the first candidate is increased and the total loss of the second candidate and the third candidate is decreased compared to the case where the output difference is 2 kW. On the other hand, when the required output difference is 4 kW, the total loss of the third candidate is the smallest, so that the power consumption of the third candidate is the smallest.

  Thus, after deriving not only the first candidate but also the first to third candidate power consumption PEn, the candidate having the smallest power consumption PEn is selected, and the front motor 102, the rear right motor 104, the rear By controlling the left motor 106, the power consumption can be suppressed as compared with the conventional one while maintaining the required driving force difference DR.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to this embodiment. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Is done.

  In the above-described embodiment, the first to third candidate power consumption PEn is derived, the candidate having the smallest power consumption PEn is selected, and the front motor 102, the rear right motor 104, and the rear left motor 106 are controlled. I tried to do it. However, the power consumption PEn of at least the first candidate and the second candidate, or the first candidate and the third candidate is derived, and the candidate with the lowest power consumption PEn is selected, and the front motor 102, the rear right motor 104, the rear The left motor 106 may be controlled.

  In the above-described embodiment, the right front wheel 110 and the left front wheel 112 are driven by the front motor 102, the right rear wheel 114 is driven by the rear right motor 104, and the left rear wheel 116 is driven by the rear left motor 106. did. However, the right front wheel 110 and the left front wheel 112 may be independently driven by separate motors, and the right rear wheel 114 and the left rear wheel 116 may be driven by one motor.

  The present invention can be used for an automobile driven only by a motor.

100 ... automobile 102 ... front motor (third motor)
104 ... Rear right motor (first motor)
106 ... Rear left motor (second motor)
110 ... Front right wheel (second right wheel)
112 ... Left front wheel (second left wheel)
114… Right rear wheel (first right wheel)
116 ... left rear wheel (first left wheel)
160 ... control unit 202 ... required driving force deriving unit 204 ... candidate driving force deriving unit 206 ... power consumption deriving unit 208 ... drive control unit

Claims (3)

A first motor for driving the first right wheel;
A second motor for driving the first left wheel;
A third motor for driving a second right wheel and a second left wheel provided forward or rearward with respect to the first right wheel and the first left wheel;
A control unit that controls driving of the first motor, the second motor, and the third motor;
With
The controller is
The first required driving force to be transmitted to the first right wheel, the second required driving force to be transmitted to the first left wheel, and the third required driving force to be transmitted to the second right wheel and the second left wheel A required driving force deriving unit that derives a total required driving force that is the sum of the first required driving force and a driving force difference between the first required driving force and the second required driving force;
Assuming that there is no driving force difference between the first required driving force and the second required driving force, the total power consumption of the first motor, the second motor, and the third motor is minimized. Determining a driving force distribution between the sum of the first required driving force and the second required driving force and the third required driving force, and based on the driving force distribution, the driving force difference, and the total required driving force. The first required driving force, the second required driving force, and the third required driving force of the first candidate are derived, and one of the first required driving force and the second required driving force is 0. The candidate driving force deriving unit for deriving the first requested driving force, the second requested driving force, and the third requested driving force of the second candidate based on the driving force difference and the total requested driving force When,
The power consumption of the first motor when driving the first right wheel with the first candidate driving force of the first candidate, and the power consumption of the first motor when driving the first left wheel with the second candidate driving force of the first candidate The sum of the power consumption of the second motor and the sum of the power consumption of the third motor when the second right wheel and the second left wheel are driven with the third candidate driving force of the first candidate is consumed by the first candidate It is derived as electric power, and when the first right wheel is driven by the first candidate driving force of the second candidate, the power consumption of the first motor, and the first candidate by the second candidate driving force of the second candidate The power consumption of the second motor when the left wheel is driven, and the power consumption of the third motor when the second right wheel and the second left wheel are driven with the third candidate driving force of the second candidate A power consumption deriving unit for deriving the sum as the power consumption of the second candidate;
A candidate with low power consumption is selected from the first candidate and the second candidate, and the first motor is driven to drive the first right wheel with the first required driving force corresponding to the selected candidate. Driving the second motor to drive the first left wheel with the second required driving force corresponding to the selected candidate, and the second right wheel with the third required driving force corresponding to the selected candidate. An automobile comprising: a drive control unit that drives the third motor so as to drive the second left wheel. The candidate driving force deriving unit
The vehicle speed, the driving force such that one of the first required driving force and the second required driving force is the maximum driving force that the corresponding first motor or the second motor can output at the current vehicle speed. Based on the difference and the total required driving force, the first required driving force, the second required driving force, and the third required driving force of a third candidate are derived,
The power consumption deriving unit
When the first right wheel is driven with the first candidate driving force of the third candidate, when the first left wheel is driven with power consumption of the first motor when the second candidate driving force of the third candidate is driven Of the second motor and the sum of the power consumption of the third motor when the second right wheel and the second left wheel are driven by the third candidate driving force of the third candidate. Derived as the power consumption of the three candidates,
The drive control unit
The automobile according to claim 1, wherein a candidate having the lowest power consumption is selected from the first candidate, the second candidate, and the third candidate. A first motor for driving the first right wheel;
A second motor for driving the first left wheel;
A third motor for driving a second right wheel and a second left wheel provided forward or rearward with respect to the first right wheel and the first left wheel;
A control unit that controls driving of the first motor, the second motor, and the third motor;
With
The controller is
The first required driving force to be transmitted to the first right wheel, the second required driving force to be transmitted to the first left wheel, and the third required driving force to be transmitted to the second right wheel and the second left wheel A required driving force deriving unit for deriving a total required driving force that is a sum of the first required driving force and a second required driving force.
Assuming that there is no driving force difference between the first required driving force and the second required driving force, the total power consumption of the first motor, the second motor, and the third motor is minimized. Determining a driving force distribution between the sum of the first required driving force and the second required driving force and the third required driving force, and based on the driving force distribution, the driving force difference, and the total required driving force. The first required driving force, the second required driving force, and the third required driving force of the first candidate are derived, and one of the first required driving force and the second required driving force corresponds. Based on the vehicle speed, the driving force difference, and the total required driving force, the first candidate of the third candidate is set so that the first motor or the second motor that can output the maximum driving force that can be output at the current vehicle speed. The required driving force, the second required driving force, and the third required driving force And the candidate driving force deriving unit that out,
The power consumption of the first motor when driving the first right wheel with the first candidate driving force of the first candidate, and the power consumption of the first motor when driving the first left wheel with the second candidate driving force of the first candidate The sum of the power consumption of the second motor and the sum of the power consumption of the third motor when the second right wheel and the second left wheel are driven with the third candidate driving force of the first candidate is consumed by the first candidate Derived as electric power, and when the first right wheel is driven with the first candidate driving force of the third candidate, the power consumption of the first motor and the first candidate with the second candidate driving force of the third candidate The power consumption of the second motor when driving the left wheel, and the power consumption of the third motor when driving the second right wheel and the second left wheel with the third candidate driving force of the third candidate A power consumption deriving unit for deriving the sum as the power consumption of the third candidate;
A candidate with low power consumption is selected from the first candidate and the third candidate, and the first motor is driven to drive the first right wheel with the first required driving force corresponding to the selected candidate. Driving the second motor to drive the first left wheel with the second required driving force corresponding to the selected candidate, and the second right wheel with the third required driving force corresponding to the selected candidate. An automobile comprising: a drive control unit that drives the third motor so as to drive the second left wheel.

Images