JP2005269793A - Hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hybrid vehicle capable of sustaining the traveling state without lowering the operability under such a state as regenerative operation is carried out through an electric motor while traveling the vehicle. <P>SOLUTION: In the hybrid vehicle arranged such that a traveling unit 3 is driven by providing an engine 1 and a motor 2 as a power source, and a means H for controlling the operating conditions of the vehicle controls operation of the motor 2 to perform powering operation and regenerative operation, operation of the motor is controlled under low regenerative torque state for reducing regenerative torque at the time of regenerative operation when a decision is made that the vehicle is traveling on an uphill road based on information detected by a vehicle speed sensor. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention comprises an engine and an electric motor as a power source to drive the traveling device, and the control means for controlling the driving state of the vehicle operates the electric motor so as to execute a power running operation and a regenerative operation. The present invention relates to a hybrid vehicle configured to control the vehicle.

  The hybrid vehicle having the above configuration includes the engine and the electric motor as a power source, and when the vehicle is required to have a large driving force, such as when starting or accelerating the vehicle, the electric motor is powered. It is designed to assist the engine power. Electric power for the electric motor is supplied from a battery mounted on the vehicle. When the vehicle speed is reduced, the electric motor is regeneratively operated to generate a braking force to reduce the vehicle speed, and the regenerative operation is performed. The battery is charged with the electric power obtained by. Further, even when the vehicle is in steady running, the regenerative operation of the electric motor is performed to charge the battery with the electric power obtained by the regenerative operation (see, for example, Patent Document 1). .

JP-A-9-233606

  In the conventional configuration described above, when the vehicle is running on the uphill from the state where the vehicle is running on a flat road in the state where the vehicle is running and the regenerative operation is performed as described above, In addition to the braking force due to torque acting, driving resistance due to climbing resistance will be added, and the vehicle speed will be reduced, so the driver will operate the accelerator so that the amount of accelerator operation becomes larger By depressing the tool, the engine output is increased to reduce the deceleration amount of the vehicle speed.

  However, in a hybrid vehicle, the output characteristics of the engine with respect to changes in the accelerator operation amount are set so that the fuel consumption is reduced, so depending on the situation of the accelerator operation by the driver. In some cases, the driving force of the vehicle does not increase so much, and at this time, the regenerative torque acts as described above, and therefore the vehicle speed may be reduced more than the driver predicted.

  Therefore, in the conventional configuration, when the vehicle travels on an uphill from a state where it is traveling on a flat road while performing regenerative operation with an electric motor, the vehicle speed is greatly reduced, and the driver is There is a disadvantage of feeling a sense of deceleration, and in such a situation, the driver always needs to change the accelerator operation amount greatly to the increase side, and there is still room for improvement in terms of driving operability.

  An object of the present invention is to provide a hybrid vehicle that can be driven in a state in which the driving operability is not deteriorated when the vehicle approaches a climbing slope in a state where a regenerative operation is performed by an electric motor while the vehicle is traveling. The point is to provide.

  The first characteristic configuration of the present invention is configured to drive the travel device by including an engine and an electric motor as a power source, and the control means for controlling the driving state of the vehicle executes the power running operation and the regenerative operation. The hybrid vehicle is configured to control the operation of the electric motor, and is provided with a traveling state detection unit that detects a traveling state of the vehicle, and the control unit is based on detection information of the traveling state detection unit. When it is determined that the vehicle is in an uphill state where the vehicle is traveling on an uphill, the operation of the electric motor is controlled in a low regenerative torque state that reduces the regenerative torque when performing the regenerative operation. There is in point.

  According to the first characteristic configuration, when the control means determines that the vehicle is in an uphill state where the vehicle is traveling uphill based on the detection information of the traveling state detection means, the regenerative torque for performing the regenerative operation is determined. Thus, the operation of the electric motor is controlled in a low regenerative torque state that reduces the above.

  In other words, the control means determines whether the vehicle is in an uphill state where the vehicle is traveling uphill based on the detection information of the traveling state detection means. This reduces the regenerative torque by reducing the braking force due to regenerative braking. As a result, even when the vehicle is traveling on a flat road to a climbing state, there is no disadvantage that the vehicle speed is greatly reduced and the driver feels a sense of deceleration. Even without performing an operation of making a large change to the increase side, it is possible to prevent the vehicle speed from being greatly decelerated by reducing the regenerative torque.

  Examples of the traveling state detection means include a configuration that detects the vehicle speed as the traveling state, or a configuration that detects an inclination angle in the longitudinal direction of the vehicle body with respect to the horizontal posture of the vehicle. In detecting the vehicle speed, it is possible to determine the flat road running resistance from the vehicle speed information, and determine whether the vehicle is in an uphill state based on the flat road running resistance and the driving force of the vehicle, It is possible to directly detect that the vehicle is in an uphill state by detecting an inclination angle in the vehicle longitudinal direction with respect to the horizontal posture of the vehicle.

  Therefore, when the vehicle is running and the regenerative operation is being performed by the electric motor, the vehicle speed increases even if the driver does not perform an operation to greatly change the accelerator operation amount to the increasing side when approaching an uphill. It has been possible to provide a hybrid vehicle that can prevent the vehicle from decelerating and that can maintain the traveling state without deteriorating the driving operability.

  According to a second characteristic configuration of the present invention, in addition to the first characteristic configuration, as the low regenerative torque state, the control means increases the regenerative torque as the deceleration amount per unit time in the uphill state increases. The point is that it is configured to have a small value.

  According to the second feature configuration, if the climbing slope is gentle, the climbing resistance is small, so the deceleration amount per unit time of the vehicle speed caused by the climbing resistance is small, and the climbing resistance increases as the climbing slope increases. The amount of deceleration per unit time increases. Therefore, since the operation of the electric motor is controlled in such a state that the regenerative torque is set to a smaller value as the deceleration amount per unit time is larger, the regenerative torque, that is, the regenerative operation control is increased as the climbing resistance increases. By setting the power to a small value, it is possible to maintain the traveling state in a state where the feeling of deceleration of the vehicle speed is suppressed and the driving operability is not deteriorated.

  According to a third feature configuration of the present invention, in addition to the first feature configuration or the second feature configuration, a vehicle speed detection unit that detects a vehicle speed is provided as the traveling state detection unit, and the control unit is configured by the vehicle speed detection unit. A running resistance calculation process for obtaining a flat road running resistance of the vehicle in a flat road running state based on the detected vehicle speed information, an output torque of the engine, a regeneration torque of the electric motor, and the engine and the electric motor The vehicle climbs based on the driving force calculation process for obtaining the driving force of the vehicle based on the speed ratio until the power of the vehicle is transmitted to the traveling device, and the driving force of the vehicle and the flat road running resistance. Each of the determination processes for determining whether or not the vehicle is in a climbing state while traveling on a hill is configured to be executed.

  According to the third characteristic configuration, the vehicle speed is detected by the vehicle speed detecting means, and the flat road running resistance of the vehicle in the flat road running state is obtained based on the vehicle speed information at that time. This flat road running resistance is a running resistance when the vehicle is running on a flat road, and the vehicle runs such as a rolling resistance when the running device is running on a flat road surface and an air resistance accompanying the running. Although the resistance components that occur sometimes are combined, such flat road running resistance generally has a correlation with the magnitude of the vehicle speed, and these correlations are set in advance as map data or arithmetic expressions. Will be. When the vehicle speed is obtained by the vehicle speed detecting means, the flat road running resistance can be obtained by using the vehicle speed information and the map data or the arithmetic expression as described above.

  On the other hand, the driving force of the vehicle based on the output torque of the engine, the regeneration torque of the electric motor, and the speed ratio until the power of the engine and the electric motor is transmitted to the travel device, that is, At that time, a driving force corresponding to the magnitude of the torque driving the traveling device is obtained. At this time, if the vehicle is traveling on a flat road, the driving force is approximately equal to or smaller than the flat road running resistance, but when the vehicle is traveling on an uphill slope As a resistance when the vehicle travels, an uphill resistance is added to the flat road running resistance, so the driving force is larger than the flat road running resistance.

  Therefore, based on the driving force of the vehicle and the flat road running resistance, it can be determined whether or not the vehicle is in an uphill state where the vehicle is climbing up a slope. That is, if the driving force of the vehicle and the flat road running resistance are substantially the same, the vehicle is not in an uphill state where the vehicle is climbing a hill. If the driving force of the vehicle is larger than the flat road running resistance, the vehicle It is possible to determine that the vehicle is climbing up a hill. In this way, it is possible to appropriately determine whether or not the vehicle is in an uphill state based on the actual traveling state of the vehicle.

Hereinafter, embodiments of a hybrid vehicle according to the present invention will be described with reference to the drawings.
As shown in FIG. 1, the hybrid vehicle is directly connected so that the travel drive engine 1 and the travel drive electric motor 2 rotate integrally. In other words, the electric motor 2 for driving driving is provided in a state directly connected to the output shaft 1a of the engine 1 for driving driving, and driving is performed by driving the left and right wheels 3 as a driving device with these powers. A drive unit KU as means is configured. The electric motor 2 is connected to the output shaft 1a of the engine 1 so that the rotor 2a rotates integrally with the same axis, and the stator 2b surrounding the outer periphery of the rotor 2a is fixed to a vehicle body support portion (not shown) in a fixed position. It becomes the structure supported.

  The electric motor 2 is applied to the output shaft 1a in a state where the operation of the engine 1 is stopped to start the engine 1, or after the engine 1 is started, On the other hand, it is possible to switch to a power running state in which a driving force in the same direction as the engine rotation direction is applied to assist or assist the power, or to a regenerative state in which the driving force is applied from the output shaft 1a. It has become. That is, the electric motor 2 is switched to a power running state in which torque is output in the same direction as the rotation direction with respect to the output shaft 1a that is rotationally driven by the engine 1, so that the engine 1 can output the desired driving force. The engine 1 is configured to assist the output of the engine 1 so as to achieve a low fuel consumption state. This operating state corresponds to the power running operation. In addition, when the electric motor performs a regenerative operation during deceleration traveling, etc., the electric power obtained by the regenerative operation is charged to the battery, or when the charge state of the battery becomes low, the electric motor is driven by the driving force of the engine. The battery is charged with the electric power generated by performing the regenerative operation. This operating state corresponds to the regenerative operation.

  The power of the drive unit KU is transmitted to the transmission 6 and is transmitted to the left and right wheels 3 via the differential mechanism 7 after being shifted by a gear-type automatic transmission mechanism inside the transmission 6.

Next, a control configuration in this hybrid vehicle will be described.
As shown in FIGS. 1 and 2, a vehicle control unit 8 that manages and manages the overall operation of the vehicle, a motor control unit 9 that controls the operation of the electric motor 2 based on control information from the vehicle control unit 8, An engine control unit 12 that automatically adjusts the output of the engine 1 based on the control information from the vehicle control unit 8, specifically, the throttle opening of the electronic throttle valve 10 and the fuel injection amount by the injector 11, is provided. A potentiometer type accelerator operation amount detection sensor S1 for detecting the operation amount of the operation tool 13, a switch type brake operation detection sensor S2 for detecting whether or not the brake operation tool 14 is depressed, the rotational speed of the electric motor 2, In other words, the rotational speed sensor S3 as rotational speed detection means for detecting the rotational speed of the output shaft 1a of the engine 1 and the rotation of the axle of the wheel 3 are detected. A vehicle speed sensor S4 which is an example of a vehicle speed detection means for detecting the vehicle speed based on the speed, a shift position sensor S5 which detects the position of the shift position lever 17, a charging state detection unit S6 which detects the charging state SOC of the battery 4, and the like. This detection information is input to the vehicle control unit 8.

  As shown in FIG. 3, the motor control unit 9 controls the driving power supplied to the electric motor 2 by converting the DC power supplied from the battery 4 into three-phase AC power, or by regenerative operation. Inverter 28 that controls the regenerative power that is generated at 2 and supplied to battery 4, and the pulse drive signal that is pulse-width modulated (PWM) based on control information from vehicle control unit 8 is supplied to each switching transistor in inverter 28. PWM control circuit 29 and the like that are supplied to each of the base terminals of the battery, and by adjusting the magnitude of the current flowing through the electric motor 2 and the frequency of the alternating current, the drive torque and the rotational speed can be adjusted, and the battery The regenerative power charged to 4 can be adjusted.

  When a description is given of a configuration for generating mechanical braking force by operating the mechanical braking means KS by the brake operating tool 14, when the brake operating tool 14 is operated by a driver's stepping operation, A master cylinder 15 having a known configuration that generates a hydraulic operating force for braking corresponding to the stepping operating force is provided, and the vicinity of the wheel 3 is generated by the hydraulic operating force output from the master cylinder 15 through the hydraulic oil supply passage 15a. The vehicle body is braked by operating a friction braking device 16 provided on the vehicle. Such a mechanical braking means KS is configured to be adjustable so that the hydraulic operating force, that is, the mechanical braking force increases as the operating force of the driver with respect to the brake operating tool 14 increases. .

  The position of the shift position lever 17 includes “P” (parking position), “R” (reverse travel position), “N” (neutral position), and “D” (forward travel position). The switching operation is appropriately performed according to the situation.

  The vehicle control unit 8 detects the detection information of the shift position sensor S5, the detection information of the accelerator operation amount detection sensor S1, the detection information of the vehicle speed sensor S4, and the charge state of the battery 4 detected by the charge state detection unit S6. Based on the information and the like, the motor control unit 9 and the engine control unit 12 are configured to command control information. The motor control unit 9 and the engine control unit 12 operate the electric motor 2 and the engine 1 based on the command information. Is configured to control. Therefore, the vehicle control unit 8, the motor control unit 9, and the engine control unit 12 constitute a control means H that controls the driving state of the vehicle.

Next, control of the engine 1 and the electric motor 2 by the control means H will be described.
When the shift position lever 17 is at “P” (parking position) or “N” (neutral position), the engine 1 is basically stopped and the power running operation and the regenerative operation by the electric motor 2 are not performed. However, when the state of charge of the battery 4 drops below the set amount and the battery 4 needs to be charged, the engine 1 is operated and the power of the engine 1 is generated by the regenerative operation of the electric motor 2. The operation of the engine 1 and the electric motor 2 is controlled so as to charge the battery 4 with electric power.

  Further, when the shift position lever 17 is operated to “D” (forward travel position) and the forward direction is commanded as the vehicle body traveling direction, the control means H is operated by depressing the accelerator operating tool 13 and the vehicle body. When the engine 1 is stopped at that time, the electric motor 2 is rotated to start the engine 1, and when the vehicle body travels forward, the output of the engine 1 is adjusted according to the accelerator operation amount, As will be described later, the operation of the electric motor 2 is controlled so as to execute a power running operation and a regenerative operation. Even when the shift position lever 17 is operated to “D” (forward travel position), the vehicle stops traveling in a state where the accelerator operation is not performed, and the charge state of the battery 4 is equal to or higher than the set value. When the engine is in a high state, it is configured to execute idle stop control for stopping the engine 1. By executing the idle stop control in this way, the fuel consumption of the engine 1 is minimized.

  When the shift position lever 17 is operated to “R” (reverse travel position) and the reverse direction is commanded as the vehicle body travel direction, the output of the engine 1 is adjusted according to the accelerator operation amount. However, for the electric motor 2, neither power running operation nor regenerative operation is performed.

Next, the power running operation and regenerative operation of the electric motor 2 by the control means H will be described.
The power running operation and the regenerative operation of the electric motor 2 are performed by obtaining a target torque based on various types of information described later and controlling the operation of the electric motor 2 so as to generate the obtained target torque. In other words, in the power running operation, the control information corresponding to the target value of the power running torque is PWM controlled so that the electric motor 2 outputs the target value of the power running torque in the same direction as the rotation direction of the engine 1. A pulse signal corresponding to the target torque for power running is applied from the PWM control circuit 29 to the base terminal of each switching transistor of the inverter 28, and the electric motor 2 assists the engine 1 with the target torque. become. In the regenerative operation, control information corresponding to the target value of the regenerative torque is supplied to the PWM control circuit 29 so that the electric motor 2 outputs the target value of the regenerative torque in the direction opposite to the rotation direction of the engine 1. The PWM control circuit 29 applies a pulse signal corresponding to the target torque for regeneration to the base terminal of each switching transistor of the inverter 28, so that the electric motor 2 has a reverse torque with respect to the engine 1, that is, The regenerative braking force is applied. Then, the electric motor 2 is driven by the power of the engine 1 to act as a generator, and the battery 4 is charged in a state where the inverter 28 is changed and adjusted to the regenerative power corresponding to the regenerative braking force.

  The control means H is configured to execute a power running operation when the accelerator operation amount exceeds a preset threshold value for start determination according to the engine rotation speed, and the accelerator operation amount is set to the engine rotation speed. Accordingly, when the engine rotational speed is the same, the power running operation is stopped when the value falls below a stop determination threshold set in advance as a value lower than the start determination threshold by the set amount.

  Further, the control means H discriminates that the vehicle is in an uphill state where the vehicle is traveling on an uphill, based on detection information of the vehicle speed sensor S4 which is an example of a traveling state detection means for detecting the traveling state of the vehicle. When this is done, the operation of the electric motor 2 is controlled in a low regenerative torque state that reduces the regenerative torque when performing the regenerative operation. Further, as the low regenerative torque state, the regenerative torque is set to a smaller value as the deceleration amount per unit time in the uphill state is larger.

  Further, the control means H is a running resistance calculation process for obtaining a flat road running resistance R of the vehicle in a flat road running state based on the vehicle speed information detected by the vehicle speed sensor S4, the output torque of the engine 1, and the electric motor 2 A driving force calculation process for obtaining the driving force F of the vehicle based on the regenerative torque and the speed ratio until the power of the engine 1 and the electric motor 2 is transmitted to the traveling device 3, and the driving force F of the vehicle And based on the flat road running resistance R, each of the discrimination | determination process which discriminate | determines whether it is the uphill state which the vehicle is driving uphill is comprised. Specifically, the output torque of the engine 1, the regenerative torque of the electric motor 2 output at that time, and the speed ratio until the power of the engine 1 and the electric motor 2 is transmitted to the wheels 3. If the driving force F of the vehicle obtained based on the vehicle is greater than the running resistance R of the vehicle in a flat road running state obtained based on the vehicle speed, it is determined that the vehicle is traveling uphill while climbing a hill. It is configured.

  Hereinafter, the control operation of the electric motor 2 of the control means H in a state in which the shift position lever 17 is operated to “D” (forward travel position) will be described based on the control flowcharts shown in FIGS. 4 and 5.

  First, a motor operating condition is determined as to whether the electric motor 2 performs a power running operation or a regenerative operation (step 1). When the description of the determination of the motor operating condition is added, as shown in FIG. 6, the accelerator operation amount detected by the accelerator operation amount detection sensor S1 is set in advance in map data with respect to the engine rotation speed at that time. When the power running start threshold ACH is exceeded, it is determined that the power running operation is being performed. The accelerator operation amount detected by the accelerator operation amount detection sensor S1 is lower by a set amount than the start determination threshold ACH when the engine 1 has the same rotation speed according to the engine 1 rotation speed. When the state becomes lower than the stop determination threshold ACL set in advance as map data, it is determined that the regenerative operation is being performed.

If it is determined that the power running operation is being performed, the regenerative torque output process is stopped when the regenerative operation is being performed at that time (steps 2 and 3), and the motor torque output is performed based on the accelerator operation amount information. A rate A is obtained (step 4). The method for obtaining the motor torque output rate A will be described. As shown in FIG. 7, the change characteristic of the motor torque output rate A, which is the change rate of the power running torque when the accelerator operation amount is changed, is preliminarily expressed by map data. Is set. The line q1 shown in FIG. 7 is a change characteristic when the state of charge SOC of the battery 4 is high, and the line q2 is a change characteristic when the state of charge SOC of the battery 4 is in a medium range. q3 is a change characteristic when the state of charge SOC of the battery 4 is in a low region. If the accelerator operation amount is zero, the motor torque output rate A is substantially zero. However, as the accelerator operation amount increases, the motor torque output rate A is set to a larger value. Then, one of the three lines q1, q2, and q3 is applied depending on the state of charge of the battery at that time.

  That is, the line corresponding to any of the three lines q1, q2, and q3 is specified based on the information on the state of charge SOC of the battery 4 detected by the state of charge detection unit S6. Then, the motor torque output rate A is obtained from the information on the accelerator operation amount detected by the line and the accelerator operation amount detection sensor S1.

  Next, the maximum torque Tm that is the maximum value of the power running torque of the electric motor 2 corresponding to the rotational speed of the electric motor 2 at that time is obtained (step 5). This maximum torque Tm corresponds to the value of the power running torque when the motor torque output rate A is the maximum value (100%). As shown in FIG. 8, a change characteristic of the maximum torque with respect to the rotation speed of the electric motor 2 is set in advance by map data. From this change characteristic and information on the rotation speed detected by the rotation speed sensor S3, The maximum torque Tm corresponding to the rotational speed of the electric motor 2 is obtained.

  Then, the target value Ts of the power running torque is obtained by multiplying the motor torque output rate A obtained as described above and the maximum torque Tm (Ts = Tm × A), and the obtained target value Ts of the power running torque is obtained. Is output to the electric motor 2 so as to output (steps 7 and 8). That is, the control information corresponding to the target value Ts of the power running torque is given to the PWM control circuit 29, and the pulse signal is applied from the PWM control circuit 29 to the base terminal of each switching transistor of the inverter 28, so that the electric motor 2 operates in the power running mode. Will do.

  The various map data set for obtaining the power running torque of the electric motor 2 as described above is the rotational speed (electrical) of the engine 1 so that the engine 1 can maintain a high combustion efficiency. In accordance with the rotational speed of the motor 2), it is set in advance based on actually measured data or the like so as to output an appropriate power running torque.

  If it is determined in step 2 that the regenerative operation is being performed, the output of the power running torque is stopped, the regenerative torque target value calculation process for obtaining the regenerative torque target value is executed, and the regenerative torque Output processing for the electric motor 2 is executed so as to output the target value (steps 9, 10, and 11).

Next, the regeneration torque target value calculation process will be described based on the flowchart of FIG.
First, based on the output torque of the engine 1, the regenerative torque that the electric motor 2 is currently outputting, and information on the gear ratio until the power of the engine 1 and the electric motor 2 is transmitted to the wheels 3. The driving force of the vehicle is obtained (step 11). The driving force of the vehicle thus obtained corresponds to the driving torque for traveling output from the traveling wheel 3.

  Next, the flat road running resistance R of the vehicle in the flat road running state is obtained based on the detected value of the vehicle speed sensor S4 (step 12). This flat road running resistance R is a resistance when the vehicle travels on a flat road, such as rolling resistance or air resistance when the wheels 3 roll on the road surface, and changes according to the vehicle speed. It can be set in advance as map data. Therefore, the flat road running resistance R is obtained from the map data set in advance and the vehicle speed information.

  Next, the acceleration corresponding torque coefficient is set under different conditions depending on whether or not the driving force F of the vehicle is greater than the flat road running resistance R. That is, it is determined whether or not the driving force F of the vehicle is greater than the flat road running resistance R (step 13), and when it is determined that the driving force F of the vehicle is not larger than the flat road running resistance R, “1” is set as the acceleration-corresponding torque coefficient B (step 14). If it is determined that the driving force F of the vehicle is greater than the flat road running resistance R, the vehicle acceleration at that time is obtained by calculation from the vehicle speed information detected by the vehicle speed sensor 4 (step 15). Then, the acceleration corresponding torque coefficient B is changed and set according to the acceleration of the vehicle (step 16).

  When this acceleration-corresponding torque coefficient B is explained, as shown in FIG. 9, in other words, the acceleration is negative (−), and the negative acceleration becomes larger, so that the value becomes smaller. The change characteristic of the acceleration-corresponding torque coefficient B with respect to the change in acceleration is set in advance as map data so that the value decreases as the deceleration amount per unit time of the vehicle increases. The acceleration-corresponding torque coefficient B is obtained from the obtained acceleration of the vehicle and set. Specifically, if the acceleration is negative, the acceleration corresponding torque coefficient B is set as a coefficient smaller than 0.8.

  Next, the vehicle speed corresponding torque coefficient C, the accelerator operation amount corresponding torque coefficient D, and the charge state corresponding torque coefficient are obtained and set based on the information on the vehicle speed, the accelerator operation amount, and the state of charge of the battery 4, respectively. To do. That is, as shown in FIG. 10, the change characteristic of the vehicle speed corresponding torque coefficient C with respect to the change of the vehicle speed is set in advance by the map data. From this map data and the vehicle speed information detected by the vehicle speed sensor S4, A vehicle speed corresponding torque coefficient C corresponding to the current vehicle speed is obtained and set (step 17). That is, when the vehicle speed is low, the rotational speed of the engine 1 is also low, and the output of the engine 1 is not increased to the extent that the electric motor 2 can be regenerated, so that no regenerative torque is generated. ing.

  Further, as shown in FIG. 11, the change characteristic of the accelerator operation amount corresponding torque coefficient D with respect to the change of the accelerator operation amount is set in advance by map data, and is detected by this map data and the accelerator operation amount detection sensor S1. From the information on the accelerator operation amount, an accelerator operation amount corresponding torque coefficient D corresponding to the accelerator operation amount at that time is obtained and set (step 18). When the accelerator operation amount increases, the driver demands acceleration. Therefore, the accelerator operation amount-corresponding torque coefficient D is set so that the regenerative torque decreases as the accelerator operation amount increases.

  Further, as shown in FIG. 12, the change characteristic of the charge state corresponding torque coefficient E with respect to the change of the state of charge SOC of the battery 4 is set in advance by map data, and is detected by this map data and the state of charge detection unit S6. From the information on the state of charge SOC of the battery 4 to be obtained, a charge state corresponding torque coefficient E corresponding to the state of charge SOC at that time is obtained and set (step 19). When the charge state of the battery 4 is low, charging by regenerative operation is necessary. When the charge state of the battery is high, the amount of charge by regenerative operation may be small, so the higher the charge state, the smaller the regenerative torque. The charging state-corresponding torque coefficient E is set in FIG.

  Then, as shown in FIG. 13, in the region of the rotational speed at which the electric motor 2 can operate, this reference regenerative torque T0 that is set as a constant value regardless of the difference in the rotational speed is used as a reference. The torque T0 is multiplied by the respective coefficients obtained as described above, that is, the acceleration-corresponding torque coefficient B, the vehicle speed-corresponding torque coefficient C, the accelerator operation amount-corresponding torque coefficient D, and the charging state-corresponding torque coefficient E. In addition, a target value Tk for the regenerative torque of the electric motor 2 is obtained (step 20). And the output process with respect to the electric motor 2 is performed so that the target value Tk of the torque for regeneration calculated | required in this way may be output (step 10).

  As described above, the target value Tk of the regenerative torque is changed and adjusted according to changes in the vehicle speed, the accelerator operation amount, and the charging state of the battery 4 at that time. For example, the charging state of the battery 4 is a lower value. When the vehicle is traveling on a flat road when the accelerator operation amount is operated with a small value, the vehicle will not decelerate, In the uphill state, the vehicle speed is reduced even when the accelerator operation amount is maintained as it is due to the uphill resistance of the vehicle. At that time, each of the vehicle speed corresponding torque coefficient C, the accelerator operation amount corresponding torque coefficient D, and the charging state corresponding torque coefficient E is maintained at substantially the same value as when traveling on a flat road. The torque coefficient is set to a value smaller than “1” as the negative acceleration when decelerating, that is, the amount of deceleration per unit time of the vehicle is larger. Since the acceleration-corresponding torque coefficient is set to “1” when the vehicle is traveling on a flat road, the value is smaller when the vehicle is climbing up a hill than when it is not climbing. In addition, the acceleration-corresponding torque coefficient is set in such a state that the smaller the amount of deceleration per unit time, the smaller the value.

  As a result, when the regenerative operation is executed while the vehicle is running, the driver operates the accelerator operation amount to the large side even when the vehicle goes uphill from a flat road running state. Even if it is not, by reducing the regenerative torque when the electric motor performs the regenerative operation, it is possible to prevent the vehicle speed from being greatly decelerated due to the occurrence of the uphill resistance.

[Another embodiment]
Hereinafter, other embodiments are listed.

(1) In the above embodiment, as the low regenerative torque state executed when it is determined that the vehicle is in the uphill state, the regenerative torque is reduced as the deceleration amount per unit time in the uphill state is larger. As described above, the acceleration-corresponding torque coefficient for determining the target value of the regenerative torque is set to be a small value. When the vehicle is in a negative state, that is, when the vehicle speed is decelerated, the acceleration-corresponding torque coefficient is set so that the acceleration becomes a constant value that is smaller than that in the positive state, that is, when the vehicle is not decelerated. You may do it.

(2) In the above embodiment, the running state detecting means is configured by a vehicle speed sensor, and the flat road running resistance of the vehicle in the flat road running state is obtained using the vehicle speed information as the running state of the vehicle. Based on the output torque, the regeneration torque of the electric motor, and the gear ratio until the power of the engine and the electric motor is transmitted to the traveling device, the driving force of the vehicle and the flat road traveling are obtained. Although it is configured to determine whether or not the vehicle is in an uphill state where the vehicle is traveling on an uphill based on the resistance, the following configuration may be used instead of such a configuration.

  For example, as a running state detecting means, an inclination angle detecting means for detecting an inclination angle from the horizontal posture of the vehicle is provided, and the vehicle is detected to detect whether the vehicle is in an uphill state by detecting the inclination state of the vehicle in the front-rear direction. It may be configured to do so.

(3) In the above embodiment, when the accelerator operation amount exceeds the start determination threshold, it is determined that the power running operation execution condition is satisfied, and when the accelerator operation amount falls below the release determination threshold, the power running is determined. Although it is configured to determine that the operation execution condition is not satisfied, it is not limited to such a configuration, and it is determined whether the power running operation execution condition is satisfied based on information on the detected value of the throttle opening. It may be configured, and it may be determined whether or not a power running operation execution condition is satisfied from information on the pressure of the intake pipe into which combustion air for the engine is taken.

(4) In the above embodiment, the configuration in which the shaft is directly connected so that the engine and the electric motor rotate integrally is exemplified. However, the configuration is not limited to the configuration in which the shaft is directly connected, and a transmission belt, It is good also as a structure linked and interlocked in the state rotated integrally via a transmission gear. Further, in place of the hybrid vehicle having a configuration in which the output shaft of the engine and the electric motor for driving are directly connected as described above, a transmission configuration in which the engine and the electric motor transmit power to the traveling device via a planetary gear mechanism or the like. May be provided.

Diagram showing schematic configuration of hybrid vehicle Control block diagram The figure which shows the control composition of the electric motor Flow chart showing control operation Flow chart showing control operation Explanatory diagram for discriminating power running operating conditions The figure which shows the relationship between the amount of accelerator operation and the motor torque output rate Diagram showing the relationship between rotational speed and maximum torque The figure which shows the relationship between acceleration and torque coefficient corresponding to acceleration The figure which shows the relationship between vehicle speed and torque coefficient corresponding to vehicle speed The figure which shows the relationship between an accelerator operation amount and the torque coefficient corresponding to an accelerator operation amount The figure which shows the relationship between a charge condition and a charge condition corresponding | compatible torque coefficient Diagram showing reference regenerative torque

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine 2 Electric motor 3 Traveling apparatus H Control means S4 Vehicle speed detection means

Claims (3)

An engine and an electric motor are provided as power sources to drive the traveling device, and a control means for controlling the driving state of the vehicle controls the operation of the electric motor so as to execute a power running operation and a regenerative operation. A hybrid vehicle configured,
A traveling state detecting means for detecting the traveling state of the vehicle is provided,
The control means is
When it is determined based on the detection information of the traveling state detecting means that the vehicle is in an uphill state where the vehicle is traveling on an uphill, the regenerative operation is performed in a low regenerative torque state that reduces the regenerative torque. A hybrid vehicle configured to control operation of an electric motor. The control means is
2. The hybrid vehicle according to claim 1, wherein, as the low regenerative torque state, the regenerative torque is set to a smaller value as the deceleration amount per unit time in the uphill state is larger. A vehicle speed detecting means for detecting a vehicle speed as the running state detecting means;
The control means is
A running resistance calculation process for obtaining a flat road running resistance of the vehicle in a flat road running state based on the vehicle speed information detected by the vehicle speed detecting means;
Driving force calculation for determining the driving force of the vehicle based on the output torque of the engine, the regenerative torque of the electric motor, and the speed ratio until the power of the engine and the electric motor is transmitted to the travel device Processing and
2. Each of the determination processes for determining whether or not the vehicle is in an uphill state in which the vehicle is traveling on an uphill is performed based on the driving force of the vehicle and the flat road running resistance. Or the hybrid vehicle of 2.

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