JP2017038470A - Electric vehicle braking control system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric automobile brake control apparatus capable of eliminating a brake force shortage for a vehicle under limitation of charging, with a configuration of a four-wheel-drive automobile that drives a front wheel and a rear wheel with respective traveling-motors.SOLUTION: During a travel of a vehicle 1, in a case where an accelerator is turned off (Yes for S2), with charging of a traveling motor 11 limited (Yes for S1), shift amounts of front and rear suspensions detected by a stroke sensor 32 is read (S3), and ground loads of front and rear wheels 3, 5 are calculated from the shift amounts (S4). Then, if the ground load of the front wheel is larger than that of the rear wheel, a front motor 4 is set toward a regeneration side and a rear motor 6 is set toward a power-running side (S6), whereas if the ground load of the front wheel is smaller than that of the rear wheel, the rear motor 6 is set toward a regeneration side and the front motor 4 is set toward the power-running side (S7), thus controlling the front and rear motors 4, 6 under regeneration or power-running on the basis of the aforementioned settings.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a braking control device for an electric vehicle, and more specifically, when the accelerator is turned off in a state where charging to a traveling battery is restricted, the charging power of the traveling battery is restricted while the charging power to the traveling battery is restricted. The present invention relates to a braking control device for an electric vehicle that secures a braking force.

  In an electric vehicle equipped with a motor as a driving power source, or a hybrid vehicle equipped with an engine and a motor as a driving power source (hereinafter collectively referred to as an electric vehicle), the accelerator is turned off while the motor is running. The vehicle is braked by generating a negative regenerative torque corresponding to engine braking by regenerative control of the traveling motor, and the generated power by the regenerative control is charged to the traveling battery and used for subsequent motor traveling.

  There is a case where a limit is imposed on the charging power to the traveling battery (hereinafter referred to as a charging limit). For example, when the SOC (State Of Charge) is equal to or higher than a predetermined value near the charging limit, or the battery temperature is When the temperature is out of the normal temperature range to the high temperature side or the low temperature side, the charging is restricted for battery protection. If the accelerator is turned off while the motor is running with such a charging restriction, the regenerative torque of the running motor must be restricted, resulting in a lack of braking force of the vehicle and an uncomfortable feeling to the driver. There's a problem.

  Therefore, for example, in the electric vehicle disclosed in Patent Document 1, the deficiency of the regenerative torque is compensated by operating the traveling motor in an inefficient region. In this electric vehicle, the driving force of the first and second motors arranged in series is transmitted to the left and right rear wheels via a differential gear mechanism, and the accelerator is turned off when the charging is limited as described above. Sometimes, one of the motors is regeneratively controlled, and the other motor is power-running controlled by the generated power. As a result, the operating range of both motors is in the direction of deterioration of efficiency, and the braking force of the vehicle is secured while continuing the charging restriction.

JP 7-99704 A

  The electric vehicle disclosed in Patent Document 1 is a rear-wheel drive vehicle. However, from the viewpoint of traveling stability, it is desirable that the electric vehicle be embodied as a four-wheel drive vehicle in which front and rear wheels are individually driven by a traveling motor. When the technical idea of Patent Document 1 is applied to such a four-wheel drive vehicle, when the accelerator is turned off due to charging restrictions, either the front wheel or the rear wheel motor is regeneratively controlled and the generated power is used. The other motor is subjected to power running control, and the difference is applied to the vehicle as a braking force.

That is, in order to generate the braking force, it is necessary to make the regenerative torque larger than the power running torque. Therefore, the magnitude of the regenerative torque and thus the braking force of the vehicle is determined by the grip limit of the wheel on the side where the regenerative torque is transmitted. Will be limited. This fact means that the original purpose of resolving the shortage of braking force of the vehicle during the charging restriction described above cannot be sufficiently achieved.
The present invention has been made to solve such problems, and the object of the present invention is to adopt a configuration of a four-wheel drive vehicle in which front wheels and rear wheels are individually driven by a traveling motor, An object of the present invention is to provide a braking control device for an electric vehicle that can solve a shortage of braking force of a vehicle that is being charged.

  In order to achieve the above object, the braking control device for an electric vehicle according to the present invention individually drives the front wheels and the rear wheels when the accelerator is turned off in a state where charging to the traveling battery is restricted. Regenerative control of any one of the motors, motor control means for executing a charge-limited braking mode in which the braking force is applied to the vehicle while controlling the other motor by powering with the generated power, and the ground load of the front and rear wheels Based on the setting, the side of the front wheel and the rear wheel where the ground load is large is set as the regeneration side, the side where the ground load is small is set as the power running side, and the motor is supplied to the motor control means based on the setting. The motor setting means to control is provided (Claim 1).

  According to the braking control device for an electric vehicle configured as described above, in the charge-limited braking mode, one of the front wheel motor and the rear wheel motor is regeneratively controlled, and the other is power-running control. It is possible to secure the braking force of the vehicle while shifting in the worsening direction and continuing the charging restriction. Since the side of the front wheel and the rear wheel with the large ground load is always set to the regenerative side, there is room for increasing the regenerative torque to the high grip limit, and the difference between the regenerative torque and the power running torque is increased. It becomes possible to set.

As another aspect, the vehicle includes a ground load calculation unit that calculates a ground load of the front wheel and the rear wheel, and the motor setting unit regenerates based on the ground load of the front wheel and the rear wheel calculated by the ground load calculation unit. And the power running side are preferably set (claim 2).
According to the braking control device for an electric vehicle configured as described above, it is possible to set the regeneration side and the power running side based on the contact loads of the front wheels and the rear wheels calculated by the contact load calculation means.

Further, as another aspect, there is provided suspension displacement detection means for detecting the displacement amounts of the suspensions of the front wheel and the rear wheel, respectively, and the ground load calculation means is the front wheel and rear wheel detected by the suspension displacement amount detection means. It is preferable to calculate the ground load of the front wheel and the rear wheel based on the displacement amount of the suspension.
According to the braking control device for an electric vehicle configured as described above, the ground load calculation means can set the regeneration side and the power running side based on the displacement amount of the suspension of the front wheels and the rear wheel detected by the suspension displacement amount detection means. It becomes.

  As another aspect, the motor setting means uses a road surface gradient while the vehicle is traveling as an index correlating with a ground load of the front wheel and the rear wheel, and determines that the vehicle is traveling on an uphill road based on the road surface gradient. In this case, the ground load on the rear wheel is considered large and the ground load on the front wheel is considered small.If it is determined that the vehicle is traveling on a downhill road, the ground load on the front wheel may be considered large and the ground load on the rear wheel may be considered small. Preferred (claim 4).

  According to the braking control apparatus for an electric vehicle configured as described above, the ground load of the front wheels and the rear wheels changes according to the road surface gradient while the vehicle is traveling. Therefore, when the vehicle is traveling on an uphill road, the rear wheel is considered to have a large ground load on the regeneration side, and the front wheel is considered to be small on the power running side. Is assumed to be on the regeneration side assuming that the ground contact load of the front wheels is large, and is set on the power running side assuming that the ground load of the rear wheels is small.

As another aspect, it is preferable that the motor setting means continues setting the regeneration side and the power running side based on the ground load until the accelerator is turned on from an off state (Claim 5).
According to the braking control device for an electric vehicle configured as described above, if the regeneration side and the power running side are switched according to a change in road surface gradient (a change in ground load) during execution of the charge limit braking mode, Although the braking force and driving force acting on the rear wheels are reversed, such a situation is prevented.

  According to the braking control device for an electric vehicle of the present invention, the configuration of a four-wheel drive vehicle in which the front wheels and the rear wheels are individually driven by the driving motor is adopted, and the shortage of the braking force of the vehicle that is being charged is solved. be able to.

1 is a schematic configuration diagram of a plug-in hybrid vehicle according to an embodiment of the present invention. It is a flowchart which shows the motor setting routine which a hybrid control unit performs. It is a flowchart which shows the braking mode switching routine which a hybrid control unit performs. It is a characteristic view which shows the change of the load distribution of the front-and-rear wheel according to the loading amount of a vehicle, and the road surface gradient, and the setting condition of the regeneration side and the power running side.

Hereinafter, an embodiment in which the present invention is embodied in a braking control device for a plug-in hybrid vehicle (hereinafter referred to as a vehicle 1) will be described.
FIG. 1 is a schematic configuration diagram of a plug-in hybrid vehicle according to an embodiment of the present invention.
The vehicle 1 of the present embodiment can travel by driving the front wheels 3 by the output of the engine 2, and also has an electric front motor 4 (traveling motor) that drives the front wheels 3 and an electric rear motor that drives the rear wheels 5. This is a four-wheel drive vehicle having 6 (travel motor).

The engine 2 can drive the drive shaft 8 of the front wheels 3 via the speed reducer 7 and can drive the motor generator 9 via the speed reducer 7 to generate electric power.
The front motor 4 is driven by a three-phase AC power supplied from a traveling battery 11 and a motor generator 9 mounted on the vehicle 1 via a front inverter 10, and is driven via a speed reducer 7. Drive. The speed reducer 7 incorporates a clutch 7 a capable of switching connection / disconnection of power between the output shaft of the engine 2 and the drive shaft 8 of the front wheel 3.

The rear motor 6 is driven by three-phase AC power supplied from the traveling battery 11 and the motor generator 9 via the rear inverter 12, and drives the drive shaft 14 of the rear wheel 5 via the speed reducer 13.
The electric power generated by the motor generator 9 can charge the traveling battery 11 via the front inverter 10 and can supply electric power to the front motor 4 and the rear motor 6.

The battery 11 for driving | running | working is comprised with secondary batteries, such as a lithium ion battery, and has the battery module which is not shown in figure comprised by integrating several battery cells. The battery 11 for driving | running | working is provided with the battery monitoring unit 11a, and SOC and temperature TBAT of the battery 11 for driving | running | working are detected by this battery monitoring unit 11a.
The front inverter 10 includes a front motor control unit 10a and a generator control unit 10b. The front motor control unit 10 a controls the output of the front motor 4 based on a control signal from the hybrid control unit 20. The generator control unit 10 b has a function of controlling the power generation amount of the motor generator 9 based on a control signal from the hybrid control unit 20.

The rear inverter 12 has a rear motor control unit 12a. The rear motor control unit 12 a has a function of controlling the output of the rear motor 6 based on a control signal from the hybrid control unit 20.
Further, the motor generator 9 can be driven by the electric power supplied from the traveling battery 11 based on the control signal from the hybrid control unit 20, and can function as a starter motor of the engine 2. Have

Further, the vehicle 1 is provided with a charger 21 that charges the traveling battery 11 with an external power source.
The hybrid control unit 20 is a control device for performing comprehensive control of the vehicle 1 and includes an input / output device, a storage device (ROM, RAM, nonvolatile RAM, etc.), a central processing unit (CPU), and the like. Composed.

  On the input side of the hybrid control unit 20, a battery monitoring unit 11a for the traveling battery 11, a front motor control unit 10a and a generator control unit 10b for the front inverter 10, a rear motor control unit 12a for the rear inverter 12, an engine control unit 22, Auxiliary devices 33 such as an accelerator opening sensor 31 for detecting the accelerator opening θacc are connected. Detection and operation information from these devices is input to the hybrid control unit 20, and for example, the rotational speed (corresponding to a detection value described later) of the front motor 4 detected by the front motor control unit 10a is input.

On the other hand, on the output side of the hybrid control unit 20, a front motor control unit 10a and a generator control unit 10b of the front inverter 10, a rear motor control unit 12a of the rear inverter 12, a speed reducer 7 (clutch 7a), and an engine control unit 22 are provided. It is connected.
The hybrid control unit 20 calculates a vehicle request output P required for driving the vehicle 1 based on the various detection amounts and various operation information, and generates an engine control unit 22, a front motor control unit 10a, a generator control. The control signal is transmitted to the unit 10b, the rear motor control unit 12a, and the speed reducer 7, and the driving mode is switched among the EV mode, the series mode, and the parallel mode, and the outputs of the engine 2, the front motor 4 and the rear motor 6 The output (generated power) of the generator 9 is controlled.

In the EV mode, the engine 2 is stopped and the front motor 4 and the rear motor 6 are driven by the electric power supplied from the traveling battery 11 to travel.
In the series mode, the clutch 7 a of the speed reducer 7 is disconnected, and the motor generator 9 is operated by the engine 2. Then, the front motor 4 and the rear motor 6 are driven to run by the electric power generated by the motor generator 9 and the electric power supplied from the running battery 11. In the series mode, the rotational speed of the engine 2 is set to a predetermined rotational speed, and surplus power is supplied to the traveling battery 11 to charge the traveling battery 11.

In the parallel mode, the clutch 7 a of the speed reducer 7 is connected, and the power is mechanically transmitted from the engine 2 via the speed reducer 7 to drive the front wheels 3. Further, the front motor 4 and the rear motor 6 are driven to run by the electric power generated by operating the motor generator 9 by the engine 2 and the electric power supplied from the running battery 11.
The hybrid control unit 20 sets the traveling mode to the parallel mode in an efficient region of the engine 2 such as a high speed region. Further, in the region excluding the parallel mode, that is, the middle / low speed region, the mode is switched between the EV mode and the series mode based on the charging rate SOC of the traveling battery 11.

  In any mode, when the accelerator is turned off, the negative vehicle request output P is set. In the EV mode and the series mode, the vehicle required output P is achieved by the front motor 4 and the rear motor 6, and in the parallel mode, the vehicle required output P is achieved by the engine 2 in addition to the motors 4 and 6. The motors 4 and 6 and the engine 2 are controlled.

  At this time, the front motor 4 and the rear motor 6 both generate negative regenerative torque by regenerative control and charge the traveling battery 11 with power generated by the regenerative control. In order to secure more generated power, for example, in the EV mode or the series mode, the torque distribution of the motors 4 and 6 is controlled to 50:50, and the operation region is maintained in a high efficiency (normal braking described later). mode).

On the other hand, the hybrid control unit 20 has a function of charging the traveling battery 11 by forcibly driving the engine 2 to generate electric power when the SOC of the traveling battery 11 falls below the allowable range.
On the other hand, the hybrid control unit 20 is based on the SOC and temperature TBAT of the traveling battery 11 input from the battery monitoring unit 11a, or when the SOC is equal to or higher than a predetermined value near the charge limit, or the temperature TBAT is higher than the normal temperature range. Alternatively, when the temperature is deviated to the low temperature side, the charging restriction is performed to limit the charging power to the traveling battery 11 for battery protection. As in the technique of Patent Document 1, when the accelerator is turned off during the motor traveling with such a charging restriction, the braking motors 4 and 6 are intentionally operated in an inefficient region to reduce the braking force. I make up for it.

  The plug-in hybrid vehicle 1 of this embodiment is a four-wheel drive vehicle in which the front wheels 3 are driven by the front motor 4 and the rear wheels 5 are driven by the rear motor 6 in order to improve running stability. The force can be controlled independently. Therefore, when the accelerator is turned off due to the charging restriction, one of the motors 4 and 6 is regeneratively controlled, and the other motor 4 and 6 is power-running controlled by the generated power, and the difference acts on the vehicle 1 as a braking force. I am letting. However, as described in [Problems to be Solved by the Invention], the magnitude of the regenerative torque, and hence the braking force of the vehicle 1, due to the grip limit of the wheels 3 and 5 on the side to which the regenerative torque (> powering torque) is transmitted. There is a problem that is limited.

In view of such problems, the present inventor has focused on the load distribution of the front and rear wheels 3 and 5. The load distribution of the front and rear wheels 3, 5 changes according to the number of passengers of the vehicle 1, the load amount of the luggage, etc., and also changes according to the road surface gradient while the vehicle 1 is traveling.
Specifically, when only the driver gets on the rear seat from the riding state, or when a load is loaded on the rear trunk, the load distribution moves from the front wheel 3 side to the rear wheel 5 side, In this case, the load distribution fluctuates more markedly as the number of rear seat passengers and the load capacity of the luggage increases. On the other hand, when the traveling vehicle 1 reaches from the flat road to the uphill road, the load distribution shifts from the front wheel 3 side to the rear wheel 5 side. Conversely, when the vehicle 1 reaches the downhill road from the flat road, the load distribution is transferred from the rear wheel 5 side to the front wheel 3. In any case, the more steep the slope of the uphill / downhill road, the more the load distribution fluctuates.

  When the load distribution changes due to such factors, the ground contact load of the front and rear wheels 3 and 5 changes, and a grip force corresponding to the ground contact load is generated in the front and rear wheels 3 and 5. Specifically, compared with the wheels 3 and 5 on the side with a small ground load, the wheels 3 and 5 on the side with a large ground load generate a relatively high grip force. On the other hand, in order to operate the front motor 4 and the rear motor 6 in an inefficient region when the accelerator is turned off due to charging restrictions, it is possible to arbitrarily set which motor 4 or 6 is to be regenerated or powered. is there.

  From the above viewpoints, the inventors have found that if regeneration is applied to the side where the ground contact load in the front wheel 3 and the rear wheel 5 is large, the regenerative torque can be increased to the maximum by using the high grip force. Therefore, in the present embodiment, the ground load of the front and rear wheels 3 and 5 is obtained while the vehicle 1 is traveling, and the motor on the side where the ground load of the front and rear wheels 3 and 5 is large when the accelerator is turned off due to the charging restriction. 4 and 6 are regeneratively controlled, and the motors 4 and 6 on the side where the ground load is small are controlled by powering.

Hereinafter, although the braking control at the time of the charge limitation performed by the hybrid control unit 20 will be described, the principle of detecting the ground load of the front and rear wheels 3 and 5 will be described prior to that.
The contact load detection principle of the present embodiment utilizes the fact that a correlation is established between the displacement amount (sink amount) of the suspension and the contact load. The relationship between the two depends on the suspension characteristics. Basically, even if the contact load is the same, the larger the spring constant, the smaller the displacement, and the two increase or decrease according to the inherent linear and nonlinear characteristics. To do. Therefore, if the suspension characteristics are known, the ground load of the front wheel 3 and the rear wheel 5 can be specified from the displacement amount of the front and rear suspensions, and the ratio of the ground load represents the load distribution of the front and rear wheels 3 and 5. Become.

  In order to detect such a displacement amount of the suspension, as shown in FIG. 1, stroke sensors 32 (suspension displacement amount detecting means) are installed on the suspensions of the right front wheel 3 and the right rear wheel 5, and these stroke sensors are provided. The displacement amount detected by 32 is input to the hybrid control unit 20. Since the displacement amounts of the left and right suspensions are almost the same, the stroke sensor 32 is provided only on the right side in this embodiment, but the stroke sensor 32 is provided on each of the left and right sides to calculate the average value of the left and right displacement amounts. Also good.

On the other hand, the hybrid control unit 20 stores a map for calculating the ground contact load from the displacement amount in advance. As described above, the relationship between the displacement amount and the ground contact load varies depending on the suspension characteristics, and the front and rear suspension characteristics are different. Therefore, maps corresponding to the respective suspension characteristics are prepared.
During traveling in the EV mode and the series mode, the hybrid control unit 20 executes the motor setting routine shown in FIG. 2 and the braking mode switching routine shown in FIG. 3 at predetermined control intervals.

  First, in step S1 of FIG. 2, it is determined whether or not charging is currently limited to limit the charging power to the battery 11 for traveling. In the subsequent step S2, whether the accelerator is turned off from the on state based on the accelerator opening θacc. Determine whether or not. When the determination of No (negative) is made at any time, the routine is once terminated, and when the determination of Yes (positive) is made at any time, the routine proceeds to step S3.

  In step S3, the displacement amount of the front and rear suspensions input from the stroke sensor 32 is read, and in the subsequent step S4, the ground load of the front and rear wheels 3 and 5 is calculated from the displacement amount (ground load calculation means). In step S5, the magnitude relation of the ground contact load of the front and rear wheels 3 and 5 is determined. When the ground load is front wheel> rear wheel, the process proceeds to step S6, the front motor 4 on the front wheel 3 side is set to the regeneration side, the rear motor 6 on the rear wheel 5 side is set to the power running side (motor setting means), Then the routine ends. In step S5, when the ground load is front wheel ≦ rear wheel, the process proceeds to step S7, the rear motor 6 is set to the regeneration side, and the front motor 4 is set to the power running side (motor setting means).

  On the other hand, in step S11 of FIG. 3, it is determined whether or not the accelerator is currently turned off. If No, the routine is terminated. When the determination in step S11 is Yes, the process proceeds to step S12 to determine whether charging is being restricted. If the determination is No, the routine ends after the normal braking mode is selected in step S13. As described above, in the normal braking mode, both the front motor 4 and the rear motor 6 are regeneratively controlled, for example, controlled in a torque distribution of 50:50, and operated in a region with good efficiency. Sufficient power is generated while generating power.

  If the determination in step S12 is Yes, the routine is terminated after the charge limiting braking mode is selected in step S13. In this charge limiting braking mode, the front motor 4 and the rear motor 6 are regeneratively controlled or powering controlled based on the settings on the regeneration side and the powering side according to the ground load of the front and rear wheels 3 and 5 according to the routine of FIG. Motor control means). Since the control contents at this time are basically the same as those disclosed in Patent Document 1, only the differences will be described.

  In the technique of Patent Document 1, regenerative control is performed on one of the first and second motors arranged in series for rear wheel drive, and the powering control is performed on the other, so that the operating range of both motors is intentionally shifted in the direction of deterioration of efficiency. The braking force of the vehicle was increased while continuing the charging limit. On the other hand, in the present embodiment, either the front motor 4 on the front wheel 3 side or the rear motor 6 on the rear wheel 5 side is regeneratively controlled, and the other is powered by the generated power. Has achieved the same effect as the technology.

The setting conditions on the regeneration side and the power running side according to the load distribution of the front and rear wheels 3 and 5 can be represented by the characteristic diagram shown in FIG. 4, and will be further described below with reference to FIG.
In the vehicle 1 of the present embodiment, since the static load distribution at the normal time when only the driver gets on is set to front wheel: rear wheel = 60: 40, this value is the value of the front and rear wheels 3, 5 on a flat road. It becomes load distribution (point a on the characteristic line L in FIG. 4). Then, on an uphill road, it moves to the right along the characteristic line L from the point a according to the increase in the road surface gradient, and on the downhill road, from the point a along the characteristic line L according to the increase in the road surface gradient (negative side). Transition to the left. The load distribution of the front and rear wheels 3 and 5 is 50:50, which is a point (point b on the characteristic line L) that has shifted slightly uphill from the flat road. The settings on the regeneration side and the power running side are switched by the processing in steps S5 to S7.

  For example, when the load distribution of the front and rear wheels 3 and 5 is reversed to 40:60 by getting on the rear seat or loading on the rear trunk, this value becomes the load distribution of the front and rear wheels 3 and 5 on a flat road (see FIG. Point a ′) on the characteristic line L ′ in FIG. Then, in the same way as described above, the load distribution of the front and rear wheels 3 and 5 is 50:50 in the same way as described above. Is a point (point b ′ on the characteristic line L ′) slightly shifted to the downhill side from the flat road, and the setting on the regeneration side and the power running side is switched with this point b ′ as a boundary.

  As described above, changes in the number of passengers and loading capacity of the vehicle 1 and changes in road surface gradient during traveling are all reflected in the load distribution of the front and rear wheels 3 and 5, with the point where the load distribution is 50:50 as a boundary. The settings for the regeneration side and powering side are switched. For this reason, in any situation, the side with the large ground load in the front wheel 3 and the rear wheel 5 is always set as the regenerative side, so that a room for increasing the regenerative torque to the high grip limit is secured.

  That is, the settings of the regenerative torque and power running torque suitable for efficiency degradation are the power that can be charged to the traveling battery 11 at that time, and the characteristics of the motors 4 and 6 (in which operating region the efficiency is degraded) However, in any case, it is necessary to operate the motors 4 and 6 in the efficiency deterioration region while suppressing the balance between regeneration and power running to the chargeable power. If the upper limit that can be set as the regenerative torque is increased, the difference between the regenerative torque and the power running torque can be set large after satisfying these requirements, and the braking force acting on the vehicle 1 can be increased.

As a result, according to the braking control device for the plug-in hybrid vehicle 1 of the present embodiment, the wheel 3, 5 set on the regeneration side is realized while realizing good running stability by adopting the configuration of the four-wheel drive vehicle. The problem that the magnitude of the regenerative torque is limited by the grip limit can be solved, and a sufficient braking force can be achieved even during the charging limit.
In addition, an increase in the grip limit of the wheels 3 and 5 on the regeneration side means that there is a margin in the grip force of the wheel 3.5 under the same regeneration torque condition. For this reason, another effect that the vehicle behavior during traveling can be maintained in a stable direction is also obtained.

  On the other hand, when the settings for the regeneration side and the power running side are determined in the routine of FIG. 2, the same regeneration and power running settings are continued until the accelerator is turned on from the OFF state in the routine of FIG. If the regeneration side and the power running side are switched in accordance with a change in road surface gradient (change in ground load) during execution of the charge limiting braking mode, the braking force and driving force acting on the front wheels 3 and the rear wheels 5 are reversed. However, such a situation can be prevented and the vehicle behavior during traveling can be kept in a more stable direction.

  This is the end of the description of the embodiment, but the aspect of the present invention is not limited to this embodiment. For example, in the above-described embodiment, the invention is embodied in the braking control device for the plug-in hybrid vehicle 1 in which the engine 2 and the motors 4 and 6 are mounted as the driving power source. However, the type of the vehicle 1 is not limited to this, for example, You may apply to the electric vehicle carrying only a front and a rear motor as a motive power source for driving | running | working.

  In the above-described embodiment, the ground load of the front and rear wheels 3 and 5 is calculated based on the displacement amount of the suspension detected by the stroke sensor 32. However, the present invention is not limited to this. For example, as described in JP-A-11-151923, a load sensor is interposed between the shock absorber and coil spring constituting the suspension and the vehicle body, and the ground load of each wheel is calculated based on the detected value. Also good. Or in the vehicle provided with the hydropneumatic suspension, you may estimate the ground load of each wheel based on the cylinder pressure.

  Moreover, in the said embodiment, although the regeneration side and the power running side of the motors 4 and 6 were set based on the ground load of the front and rear wheels 3 and 5, it is not always necessary to use the ground load itself as an index. For example, since the ground loads on the front wheels 3 and the rear wheels 5 change according to the road surface gradient while the vehicle 1 is traveling, the road surface gradient can be regarded as an index correlated with the ground load. Therefore, when the vehicle 1 is traveling on an uphill road, the grounding load of the rear wheel 5 is regarded as being large, and the grounding load of the front wheel 3 is regarded as being small and is set to the powering side, and traveling on the downhill road. In this case, the grounding load on the front wheel 3 may be regarded as being large and set on the regeneration side, and the grounding load on the rear wheel 5 may be regarded as being small and set on the power running side. In addition, the method of estimating a road surface gradient is well known, for example, what is described in JP-A-2003-97945 may be applied.

1 Plug-in hybrid vehicle 1 (vehicle)
3 Front Wheel 4 Front Motor 5 Rear Wheel 6 Rear Motor 11 Traveling Battery 20 Hybrid Control Unit
(Motor control means, motor setting means, ground load calculation means)
32 Stroke sensor (suspension displacement detection means)

Claims (5)

When the accelerator is turned off while charging to the battery for travel is restricted, either one of the motors that individually drive the front and rear wheels is regeneratively controlled, and the other motor is powered by the generated power. Motor control means for executing a charge limiting braking mode for applying a braking force to the vehicle while controlling;
Based on the ground contact load of the front wheel and the rear wheel, the side of the front wheel and the rear wheel where the ground load is large is set as the regeneration side, and the side where the ground load is small is set as the power running side. An electric vehicle braking control device comprising: motor setting means for controlling the motor based on the motor control means. A ground load calculating means for calculating a ground load of the front wheel and the rear wheel;
2. The electric vehicle braking control according to claim 1, wherein the motor setting unit sets a regeneration side and a power running side based on the grounding load of the front wheel and the rear wheel calculated by the grounding load calculation unit. apparatus. Suspension displacement detection means for detecting the displacement amount of the suspension of the front wheel and the rear wheel,
The ground contact load calculation means calculates the ground load of the front wheel and the rear wheel based on the displacement amount of the suspension of the front wheel and the rear wheel detected by the suspension displacement amount detection means. Electric vehicle braking control device. The motor setting means uses a road surface gradient when the vehicle is traveling as an index that correlates with the contact loads of the front wheels and the rear wheels, and determines that the vehicle is traveling on an uphill road based on the road surface gradient. The ground contact load of the front wheel is considered to be small, the ground contact load of the front wheel is considered to be small, and if it is determined that the vehicle is traveling on a downhill road, the ground load of the front wheel is considered large and the ground load of the rear wheel is considered to be small. The braking control apparatus for an electric vehicle according to any one of 1 to 3. 5. The electric motor according to claim 1, wherein the motor setting unit continues to set the regeneration side and the power running side based on the ground load until the accelerator is turned on from an off state. Automotive braking control device.

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