JP6064375B2 - Electric vehicle - Google Patents

Description

  The present invention relates to a vehicle capable of braking by generating reverse torque in a motor for traveling.

  A technique related to a vehicle capable of performing braking by generating reverse torque in a traveling motor, that is, reverse braking is known (see, for example, [Patent Document 1]). In this technique, reverse braking is performed when the brake pedal force exceeds a predetermined value.

Japanese Patent Laid-Open No. 4-145805

  However, if reverse braking is performed at a constant strength at all times, for example, there is a concern that an overload is applied to the axle or the like and the traveling state of the vehicle becomes unstable. For example, when the vehicle is traveling at high speed, such a concern is increased.

  An object of the present invention is to provide a vehicle capable of appropriately performing reverse braking according to the vehicle speed, for example.

  In order to achieve the above object, an invention according to claim 1 is a vehicle that travels forward when torque is generated in the forward rotation direction of a traveling motor, vehicle speed detecting means for detecting the vehicle speed of the vehicle, and the vehicle Vehicle posture detecting means for detecting the posture of the vehicle, running state detecting means for detecting the running state of the vehicle from the vehicle speed and posture of the vehicle, and torque generated intermittently in the reverse rotation direction of the running motor. And a control means for generating a reverse braking force, wherein the control means varies a generation amount of the reverse braking force based on a running state detected by the running state detecting means.

In the first aspect of the present invention , the control means includes calculation means for calculating the maximum amount of reverse braking force required to stop the vehicle, and the control means is stepwise up to the maximum generation amount. It is characterized by increasing the generation amount.

According to a second aspect of the present invention, the vehicle attitude detection means has front and rear wheel rotation difference detection means for detecting a rotation difference between the front and rear wheels of the vehicle, and the control means rotates the front and rear wheels with a predetermined rotation difference. when exceeding the difference between the target value, in the vehicle according to claim 1, characterized by varying the generation amount such that the said predetermined front and rear wheel rotational difference target value.

According to a third aspect of the present invention, the vehicle attitude detection means has vertical gravity detection means for detecting longitudinal gravity applied to the front and rear of the vehicle, and the control means has the vertical gravity exceeding a predetermined vertical gravity target value. 3. The vehicle according to claim 1, wherein the generation amount is varied so that the predetermined vertical gravity target value is obtained.

According to a fourth aspect of the present invention, there is provided a battery for supplying electric power to the traveling motor, a regenerative braking means by the traveling motor, a regenerative charging means for charging the battery by the regenerative braking means, and a charging state of the battery. Battery state detection means for detecting, and regenerative charge availability determination means for determining whether or not regenerative charging is possible based on the battery charge state and the running state, and the control means includes the regenerative charge availability determination means. The vehicle according to any one of claims 1 to 3, wherein the reverse braking force is generated when it is determined as impossible.

According to a fifth aspect of the present invention, an abnormality of the braking device is detected based on a hydraulic brake device, a brake pedal depression amount detecting means for detecting a depression amount of the brake pedal, and the depression amount and the vehicle speed of the vehicle. to a hydraulic braking system abnormality detecting means, the control means, said abnormality of any one of claims 1 4, characterized in that for generating the reverse braking force when detected In the vehicle.

According to a sixth aspect of the present invention, the travel motor includes a front wheel motor that drives a front wheel of the vehicle and a rear wheel motor that drives a rear wheel, and the control means includes the front wheel motor, the rear wheel motor, there each of the generation amount of the vehicle according to claim 1, any one of the 5, characterized in that the variable.

  The invention according to claim 1 is a vehicle that travels forward when torque is generated in the forward rotation direction of the traveling motor, and a vehicle speed detecting means that detects the vehicle speed of the vehicle, and a vehicle attitude that detects the attitude of the vehicle. A detecting means, a running condition detecting means for detecting the running condition of the vehicle from the vehicle speed and attitude of the vehicle, and a control for generating reverse braking force by intermittently generating torque in the reverse rotation direction of the running motor. And the control means is in a vehicle that varies the amount of reverse braking force generated based on the running state detected by the running state detecting means, and therefore the vehicle running state including the vehicle speed and the vehicle attitude Accordingly, it is possible to provide a vehicle that can intermittently generate reverse braking force in accordance with the above, and can enhance safety during reverse braking.

Further, in the invention according to claim 1 , the control means includes a calculation means for calculating a maximum generation amount of the reverse braking force necessary for stopping the vehicle, and the control means performs steps up to the maximum generation amount. since manner the generation amount of the in vehicles you characterized by large, generated to increase intermittently and stepwise reverse braking force according to the running condition of the vehicle including the attitude of the vehicle speed and the vehicle Therefore, it is possible to provide a vehicle that can be stopped quickly while improving safety during reverse braking.

According to a second aspect of the present invention, the vehicle attitude detection means has front and rear wheel rotation difference detection means for detecting a rotation difference between the front and rear wheels of the vehicle, and the control means rotates the front and rear wheels with a predetermined rotation difference. when exceeding the difference between the target value, since the vehicle according to claim 1, characterized by varying the generation amount such that the said predetermined front and rear wheel rotational speed difference target value, the rotational difference between the vehicle speed and the front and rear wheels To provide a vehicle capable of intermittently generating reverse braking force in accordance with the running state of the vehicle including the posture of the vehicle influenced by the vehicle and capable of improving safety during reverse braking Can do.

According to a third aspect of the present invention, the vehicle attitude detection means has vertical gravity detection means for detecting longitudinal gravity applied to the front and rear of the vehicle, and the control means has the vertical gravity exceeding a predetermined vertical gravity target value. when, because the vehicle according to claim 1 or 2, characterized in that varying the generation amount such that the predetermined longitudinal gravity target value is affected by the vertical gravitational force before and after the vehicle speed and the vehicle Therefore, it is possible to provide a vehicle that can intermittently generate a reverse braking force in accordance with the traveling state of the vehicle including the posture of the vehicle and can improve safety during reverse braking.

According to a fourth aspect of the present invention, there is provided a battery for supplying electric power to the traveling motor, a regenerative braking means by the traveling motor, a regenerative charging means for charging the battery by the regenerative braking means, and a charging state of the battery. Battery state detection means for detecting, and regenerative charge availability determination means for determining whether or not regenerative charging is possible based on the battery charge state and the running state, and the control means includes the regenerative charge availability determination means. The vehicle according to any one of claims 1 to 3, wherein the reverse braking force is generated when it is determined that it is impossible, so that the vehicle according to a running state of the vehicle including a vehicle speed and a posture of the vehicle. It is possible to generate reverse braking force intermittently and to improve safety during reverse braking, and for driving within the range where regenerative charging of the battery is possible It is possible to provide a vehicle capable of performing regeneration by braking without using a plugging by chromatography data.

According to a fifth aspect of the present invention, an abnormality of the braking device is detected based on a hydraulic brake device, a brake pedal depression amount detecting means for detecting a depression amount of the brake pedal, and the depression amount and the vehicle speed of the vehicle. to a hydraulic braking system abnormality detecting means, the control means, said abnormality of any one of claims 1 4, characterized in that for generating the reverse braking force when detected Since it is in the vehicle, it is possible to perform reverse braking as emergency braking in the event of an abnormality in the braking device, and intermittently generate reverse braking force according to the running state of the vehicle including the vehicle speed and the attitude of the vehicle Therefore, it is possible to provide a vehicle capable of improving safety during reverse braking.

According to a sixth aspect of the present invention, the travel motor includes a front wheel motor that drives a front wheel of the vehicle and a rear wheel motor that drives a rear wheel, and the control means includes the front wheel motor, the rear wheel motor, since each of the generation amount of the vehicle according to claim 1, any one of 5, which comprises a variable, the front wheel motor in accordance with the running condition of the vehicle including the attitude of the vehicle speed and the vehicle It is possible to provide a vehicle that can intermittently generate a reverse braking force for each of the rear wheel motors and can enhance safety during reverse braking.

1 is a block diagram showing a schematic configuration according to an embodiment of a vehicle to which the present invention is applied. It is the block diagram which showed schematic structure regarding the control system of the vehicle shown in FIG. FIG. 2 is a schematic front view showing a drive system provided in the vehicle shown in FIG. 1 and transmitting an output of a traveling motor. 2 is a flowchart showing an outline of control when reverse braking is performed in the vehicle shown in FIG. 1. FIG. 2 is a conceptual diagram illustrating an example of a signal input to a traveling motor when reverse braking is performed in the vehicle illustrated in FIG. 1. 2 is a flowchart illustrating an example of control when reverse braking is performed in the vehicle illustrated in FIG. 1. 2 is a flowchart showing an outline of a part of control when reverse braking is performed in the vehicle shown in FIG. 1. 2 is a timing chart illustrating an example in which a signal input to a traveling motor is adjusted in accordance with a traveling state of the vehicle when reverse braking is performed in the vehicle illustrated in FIG. 1. FIG. 2 is a conceptual diagram illustrating an example of how a signal input to a traveling motor is adjusted according to the traveling state of the vehicle when reverse braking is performed in the vehicle illustrated in FIG. 1. It is the block diagram which showed the one part schematic structure of the other structural example of the vehicle which can apply this invention.

FIG. 1 shows a schematic configuration mainly relating to a drive system of a vehicle to which the present invention is applied.
This vehicle 100 is an electric vehicle (EV) equipped with a motor 10a, which is a front wheel motor for driving front wheels, and a motor 10b, which is a rear wheel motor for driving rear wheels, as driving motors as driving motors. It is an electric vehicle.

  In addition to the motors 10a and 10b, the vehicle 100 converts a high-voltage battery 20 that is a large-capacity battery using a storage battery that supplies electric power to the motors 10a and 10b, and the electric power supplied from the high-voltage battery 20 and a predetermined amount. Inverters 30a and 30b, which are motor inverters for driving the motors 10a and 10b by supplying them to the motors 10a and 10b.

  The vehicle 100 also includes a converter 40 which is a DC / DC converter connected between the high voltage battery 20 and the inverter 30a, an air conditioner and / or a heater 50 (hereinafter, air conditioner 50), a high voltage battery 20 and an inverter 30a. A switch 41 that is a relay switch for the converter 40 interposed between the converter 40, a switch 51 that is a relay switch for the air conditioner 50 interposed between the high voltage battery 20 and the inverter 30 a and the air conditioner 50, and the converter 40 And a 12V battery 42 and a cooling fan (not shown) for cooling the high voltage battery 20.

  The vehicle 100 also includes a front wheel drive shaft 61 that is rotationally driven by the motor 10a and a drive wheel 62 that is a front wheel, and a rear wheel drive shaft 63 that is rotationally driven by the motor 10b and a rear wheel. The driving wheel 64, the front wheel T / A having a built-in differential (not shown) that transmits the driving force of the motor 10a to the driving wheel 62 via the driving shaft 61, that is, the transaxle 70a, and the driving force of the motor 10b. The rear wheel T / A, that is, the transaxle 70b, which has a differential (not shown) and is transmitted to the drive wheel 64 via the drive shaft 63, is provided.

  The vehicle 100 also stops the operation of the transaxle 70a so that the electric parking lock means 80 for putting the vehicle 100 into a parking state, and how to collect information on the vehicle 100 and move the system of the vehicle 100 are moved. And an ECU 90 as an EV ECU, which is a control means that functions as an integrated controller that plays a role of determining.

  The vehicle 100 also includes a steering wheel S operated by the driver, a steering angle sensor 91 that detects the steering angle of the steering wheel S and inputs the steering angle to the ECU 90, and a braking member that is operated by the driver to brake the vehicle 100. Brake pedal B as a brake pedal, and a brake depression degree detection sensor as a braking operation detection means that is a brake pedal depression amount detection means that detects a depression amount that is a stroke amount as an operation state of the brake pedal B, that is, a brake pedal depression amount detection means that inputs to the ECU 90 92, an accelerator pedal A as an accelerator member operated by the driver, an accelerator opening detection sensor 93 that detects a stroke amount, that is, a stepping degree as an operation state of the accelerator pedal A, and inputs it to the ECU 90, and an operation by the driver And a side brake lever (not shown).

  Although the vehicle 100 is shown only on the right side of the drive shaft 63, the vehicle 100 is provided on the left and right sides of the drive shafts 61 and 63, detects a vehicle speed, and functions as vehicle speed detection means for inputting the detected vehicle speed to the ECU 90. Although shown only on the right side, a braking portion 66 provided with brake pads (not shown) that is provided on the left and right sides of the driving wheels 62 and 64 and applies braking resistance to the driving wheels 62 and 64 to brake the vehicle 100; have.

  The vehicle 100 also includes an electric actuator (not shown), a brake hose, and the like that brake the vehicle 100 by hydraulically driving the braking unit 66 based on the depression degree of the brake pedal B detected by the brake depression degree detection sensor 92. Braking means 67, which is a hydraulic braking device, and electric side brake means 68 for driving the braking portion 66 with a wire or the like (not shown) to brake the vehicle 100 when the side brake lever is pulled. doing.

  As shown in FIG. 2, the vehicle 100 also detects SOC (State of Charge) that is a charged state of the high voltage battery 20 and inputs the detected SOC to the ECU 60 in addition to the SOC detection means 94 as battery state detection means 94. Further, a yaw rate sensor 95, a pitch sensor 96, a vertical G sensor 98, a leveling sensor 99, and the like are provided, and detected values by these sensors are input to the ECU 90 as signals.

  These sensors are well known, and are not necessarily provided independently, for example, the yaw rate sensor 95 is appropriately substituted by another sensor such as the wheel rotation sensor 65. The same applies to each sensor indicated by a reference numeral in FIG.

  2, for example, the vehicle 100 drives the left and right wheels of the drive wheels 62 with independent motors 10a and 10a as shown in FIG. This is provided when the left and right wheels of the drive wheel 64 are driven by independent motors 10b and 10b. 7 to 9, the part shown in the brackets is adopted when the vehicle 100 has the configuration shown in FIG. 10.

  The vehicle 100 includes a headlight, a hazard lamp, a horn, and the like, although not shown. These are well-known ones, and their operation is controlled by the ECU 90. For example, the vehicle is driven by the ECU 90 to notify the surroundings of the vehicle 100 in an emergency.

  Motors 10a and 10b, which are traveling motors, are driven by electric power input from high-voltage battery 20 via inverters 30a and 30b, and drive wheels 62 and 64 via transaxles 70a and 70b and drive shafts 61 and 63, respectively. Is driven to drive the vehicle 100.

  When the motors 10a and 10b generate torque in the forward rotation direction, the vehicle 100 travels forward, and when the torque is generated in the reverse rotation direction, the vehicle 100 travels backward.

  The motors 10a and 10b also function as a generator that converts the kinetic energy of the vehicle 100 at the time of deceleration through the drive wheels 62 and 64, the drive shafts 61 and 63, and the transaxles 70a and 70b and converts them into electrical energy. To do. As described above, the vehicle 100 is regenerated by four wheels during deceleration, and the motors 10a and 10b function as regenerative braking means.

  The inverters 30a and 30b supply the power of the high voltage battery 20 to the motors 10a and 10b with a predetermined output when the motors 10a and 10b are driven, and are generated by the motors 10a and 10b when the motors 10a and 10b function as generators. The rectified power is rectified and output. This output is used for charging the high voltage battery 20, charging the battery 42 by the converter 40, indoor air conditioning of the vehicle 100 by driving the air conditioner 50, cooling the high voltage battery 20 by a cooling fan, and the like. The inverters 30a and 30b function as regenerative charging means in that the high voltage battery 20 is charged by outputs from the motors 10a and 10b that function as regenerative braking means.

  The ECU 90 includes a CPU, a memory, and a timer (not shown). The ECU 90 collects information related to the general state of the vehicle 100 including the above-described components, and controls driving of the vehicle 100 in general.

  For example, the ECU 90 drives the motors 10a and 10b according to the operation state to accelerate the vehicle 100 when the accelerator opening detection sensor 93 detects that the accelerator pedal A is depressed. Functions as motor control means. In this embodiment, the accelerator opening detection sensor 93 detects the depression amount, which is the degree of depression of the accelerator pedal A, as the operation state. However, the operation state may include the depression speed of the accelerator pedal A.

  Further, when the ECU 90 detects that the brake pedal B is depressed by the brake depression degree detection sensor 92, the ECU 90 drives the braking means 67 according to the operation state to brake or decelerate the vehicle 100. It functions as a braking control means. In this embodiment, the brake depression degree detection sensor 92 detects the depression amount that is the depression degree of the brake pedal B as the operation state. However, the operation state may include the depression speed of the brake pedal B.

  Further, the ECU 90 detects that the depression operation of the brake pedal B is being performed by the brake depression degree detection sensor 92, and when a predetermined condition described later is satisfied, the motor 10a and the motor 10b It functions as a regeneration control means for performing regeneration using at least one of the above.

  Further, the ECU 90 serves as a side brake control unit that operates the side brake unit 68 to brake the vehicle 100 not only when the side brake lever is pulled but also when a predetermined condition described later is satisfied. Function.

  Further, the ECU 90 detects that the depression operation of the brake pedal B is performed by the brake depression degree detection sensor 92, and when the braking means 67 is operated under the control of the ECU 90 functioning as the braking control means, Based on the vehicle speed detected by the wheel rotation sensor 65, the degree of braking by the braking means 67, in other words, whether or not the deceleration is normal, that is, whether or not the braking means 67 is functioning normally, is determined. It functions as a braking degree determining means as a hydraulic braking device abnormality detecting means for detecting 67 abnormality.

  In addition, when the vehicle 100 is traveling, the ECU 90 detects that the brake pedal B is depressed by the brake depression degree detection sensor 92, or the ECU 90 that functions as the braking degree determination means determines that the braking degree is not normal. That is, when a predetermined condition to be described later is satisfied, for example, it is determined that the braking means 67 is not functioning normally, the motor 10a and / or the motor 10b is rotated in the reverse direction. It functions as reverse braking control means for generating reverse braking by generating braking, that is, reverse braking force.

  Further, the ECU 90 is based on detection values input from the wheel rotation sensor 65, yaw rate sensor 95, pitch sensor 96, vertical G sensor 98, leveling sensor 99, or in addition to detection values input from the lateral G sensor 97. Thus, it functions as vehicle posture detection means for detecting the posture of the vehicle 100. Specifically, as shown in FIG. 2, the ECU 90 that functions as a vehicle attitude detection unit is a front and rear wheel that is the difference between the rotational speed of the driving wheel 62 detected by the wheel rotation sensor 65 and the rotational speed of the driving wheel 64. Detects the rotation difference. In this regard, the ECU 90 that functions as vehicle posture detection means functions as front and rear wheel rotation difference detection means. Further, the ECU 90 that functions as a vehicle attitude detection unit functions as a vertical gravity detection unit that detects vertical gravity applied to the front and rear of the vehicle 100 based on a detection value detected by the vertical G sensor.

  Further, the ECU 90 functions as a traveling state detection unit that detects the traveling state of the vehicle 100. This traveling state includes at least the vehicle speed detected by the wheel rotation sensor 65, and more preferably, the vehicle speed detected by the wheel rotation sensor 65 and the ECU 90 functioning as vehicle posture detection means as in this embodiment. At least the attitude of the vehicle 100. In the present embodiment, the steering angle of the steering wheel S detected by the steering angle sensor 91, the SOC of the high voltage battery 20 detected by the SOC detection means 94, the yaw rate of the vehicle 100 detected by the yaw rate sensor 95, and the pitch sensor 96. 10, the pitch of the vehicle 100 detected by the vertical G sensor 98, the vertical G of the vehicle 100 detected by the vertical G sensor 98, and the level of the vehicle 100 detected by the leveling sensor 99 are included in the configuration shown in FIG. In addition, the lateral G of the vehicle 100 detected by the lateral G sensor 97 may be included.

  Further, the ECU 90 drives the motors 10a and 10b and activates the braking unit 67 so that the running posture of the vehicle 100 is stabilized based on the running state of the vehicle 100 detected by the ECU 90 functioning as the running state detecting unit. It functions as a vehicle attitude control means for adjusting the state and the like.

  Further, the ECU 90 determines that the braking degree is not normal by the ECU 90 functioning as a braking degree determination unit when the vehicle 100 is traveling, that is, the braking unit 67 is not functioning normally and the braking unit 67 is abnormal. Is detected based on the traveling state of the vehicle 100 detected by the ECU 90 functioning as the traveling state detecting means, in particular, the vehicle speed and the SOC of the high voltage battery 20 detected by the SOC detecting means 94. When the regeneration to 20 is performed, it functions as an overcharge determination means as a regenerative charge availability determination means for determining whether or not the rechargeable charge is possible by determining whether or not the high voltage battery 20 is overcharged.

  By the way, when the ECU 90 functions as a reverse braking control means to perform reverse rotation of the motor 10a and / or the motor 10b and perform reverse braking, if the reverse braking is always performed at a constant strength, the vehicle 100 drive system or the like may be excessive. There is a concern that the driving may become unstable due to the load being applied or the driving state of the vehicle 100 may be in the slip mode. For example, when the vehicle 100 is traveling at a high speed, such a concern is increased.

  More specifically, the vehicle 100 may be overloaded. As shown in FIG. 3, when gears 71 and 72 meshing with each other are built in the transaxles 70 a and 70 b, these gears 71 are arranged. , 72 can be damaged by overloading the teeth and meshing portions. This is because the strength of the tooth portions and the meshing portions of the gears 71 and 72 has an allowable range for friction and the like. Further, since the axle 61 and / or the axle 63 has an allowable torque against torsion, the axle 61 and / or the axle 63 may be damaged by being overloaded by torsion.

When such damage occurs, reverse braking becomes difficult.
Further, even if the traveling state of the vehicle 100 becomes unstable, reverse braking can be difficult, and a safe stop can be difficult.

  Therefore, in the vehicle 100, the ECU 90 that functions as the reverse braking control means detects the excess of the vehicle 100 based on the traveling state that is detected by the ECU 90 that functions as the traveling state detection means and includes the vehicle speed and posture of the vehicle 100. In order to avoid instability of the load and the posture of the vehicle 100, the braking degree by reverse braking, in other words, the deceleration is adjusted. In this regard, the ECU 90 that functions as reverse braking control means also functions as vehicle attitude control means.

FIG. 4 shows a schematic flowchart in the case where such control is performed by the ECU 90 functioning as reverse braking control means.
In this embodiment, it is assumed that reverse braking is performed as emergency braking, that is, emergency braking.

  First, when the depression operation of the brake pedal B is detected by the brake depression degree detection sensor 92, and it is detected that the depression degree is 100% full because emergency braking is assumed in this embodiment (S11). Based on the signal from the wheel rotation sensor 65 that functions as the vehicle speed detection means, the ECU 90 that functions as the braking degree determination means determines whether or not the deceleration is normal (S12). If the number is small, it is determined that the braking means 67 is not functioning normally and an abnormality of the brake system is determined (S13).

Such an abnormality in the brake mechanism
1. Brake hose air smear 2. 2. Phenomenon similar to air dust caused by increased water content due to no brake fluid replacement. 3. Brake pad shoe remaining phenomenon It occurs due to a failure of the mechanism itself.

  Supplementally, an increase in the amount of water due to no brake fluid replacement causes a decrease in the fluid boiling point, and vaporization occurs due to an increase in the fluid temperature when the brake is used, causing a phenomenon similar to that of an air bag. In recent years, cost reductions such as user vehicle inspections have progressed, and some users do not care about replacement of brake fluid at all, and this abnormality is likely to occur.

  Further, the brake pad shoe is less effective when the remaining amount is reduced. When the brake pad shoe disappears, a sound is generated during braking to prompt replacement.

  The failure of the mechanism itself is caused by breakage of the brake itself such as the brake hose. Other causes for this include breakage and malfunction of the vacuum pump, and even in such a case, the effectiveness of the brake is reduced.

  If it is determined in step S13 that the brake system is abnormal, surroundings are informed that the vehicle 100 is in an emergency state by appropriate operations such as lighting of headlights and hazard lamps, and intermittent operation of horns. However, this is performed as necessary, and is not essential.

  Next, regeneration control is performed by the ECU 90 functioning as regeneration control means (S15), but when the ECU 90 functioning as traveling state detection means detects that there is no decrease in speed due to regeneration, or there is little decrease, or When the SOC detection means 94 determines that overcharge occurs when the regeneration is performed by the ECU 90 functioning as an overcharge determination means when the SOC is close to the upper limit and the battery voltage is close to the upper limit, it is determined that regenerative charge is impossible. In this case, reverse braking by the motor 10a and / or the motor 10b is performed under the control of the ECU 90 functioning as reverse braking control means (S16).

  Thus, reverse braking functions as reverse braking control means on condition that the ECU 90 functioning as braking degree determination means determines that the deceleration is not normal, that is, an abnormality of the braking means 67 is detected. This is performed under the control of the ECU 90.

  Further, in this flow, the determination of the possibility of overcharging by the ECU 90 functioning as the overcharge determining means is performed on the condition that the ECU 90 functioning as the braking degree determining means determines that the deceleration is not normal. It has become.

  Then, if it is determined by the ECU 90 functioning as the overcharge determining means that the overcharge is not caused, regeneration is performed under the control of the ECU 90 functioning as the regeneration control means, and the function as the overcharge determining means is performed. If the ECU 90 determines that overcharging occurs, reverse braking is performed under the control of the ECU 90 functioning as reverse braking control means.

  Since the traveling state of the vehicle 100 is likely to become unstable during reverse braking, the ECU 90 that functions as the vehicle attitude control unit simultaneously with the reverse braking is based on the traveling state of the vehicle 100 detected by the ECU 90 that functions as the traveling state detection unit. Then, control for stabilizing the traveling posture of the vehicle 100 is performed (S16).

  Then, when the vehicle speed is 0 km and the vehicle 100 stops, these controls are stopped. As will be described later, when the vehicle speed is reduced to a predetermined speed at which braking by the side brake means 68 is performed, the braking by the side brake means 68 is activated by the ECU 90 functioning as the side brake control means, and the vehicle 100 is stopped. In this state, this braking is maintained. Therefore, even if an abnormality occurs in the brake system, the vehicle 100 is prevented from moving and safety is improved.

  The reverse braking performed as described above uses a motor characteristic that the rotation direction is not questioned, unlike an internal combustion engine such as an engine in which the intake side and the exhaust side are determined and the rotation direction is restricted. Is done by generating

Further, since the motor has a good response and can be precisely controlled, it is possible to perform reverse braking with high accuracy.
For example, in the vehicle 100, the ECU 90 functioning as the reverse braking control means and the vehicle posture control means determines the amount of reverse braking force generated based on the traveling state of the vehicle 100 detected by the ECU 90 functioning as the traveling state detecting means. Variable and adjust. Specifically, as shown in FIG. 5, a signal input to the motors 10a and 10b is generated in a pulse shape to perform reverse braking.

  A pulsed signal is intermittently input to the motors 10a and 10b via the inverters 30a and 30b for controlling the motors 10a and 10b, respectively, thereby intermittently generating torque in the reverse rotation direction of the motors 10a and 10b. Since the reverse braking is performed by generating the reverse braking force, the overload on the vehicle 100 is avoided, and the outputs of the motors 10a and 10b that cause the posture of the vehicle 100 to become unstable are avoided. This improves the safety during reverse braking.

  In particular, as shown in the figure, the pulse-like signal is generated so that its time width and amplitude, that is, the magnitude of the reverse torque gradually increase, and is input to the motors 10a and 10b. When the vehicle speed is high, reverse braking is performed while avoiding an overload on the vehicle 100, and a large reverse braking force is obtained as the vehicle speed decreases, so that the time until stopping is shortened. It is done. It should be noted that the time width and the amplitude need only gradually increase so that at least one of these advantages can be obtained. Further, it is only necessary to generate and input a pulse-like signal so that at least one of avoiding overload and avoiding instability of traveling is performed.

  As shown in the figure, the value of reverse torque due to reverse braking is considered to be a margin ratio in the most severe condition calculated by combining vehicle speed, vehicle weight, friction between wheels and road surface, etc. It is determined so as to avoid overloading and instability of running.

  In this determination, the ECU 90 functioning as a reverse braking control unit first functions as a calculating unit that calculates the maximum generation amount of the reverse braking force necessary for stopping the vehicle 100. The ECU 90 functioning as a calculation means further generates the reverse braking force so that the amount of reverse braking force generated until the reverse braking force reaches the maximum generated amount increases stepwise as shown in FIG. Determine the amount.

Then, in accordance with each determined amount of reverse braking force generated, pulse signals are sequentially input to the motors 10a and 10b to perform reverse braking. When determining the generation amount of the reverse braking force, each generation amount is set in a range that does not cause an overload on the vehicle 100 and unstable driving.
A more specific method for determining the amount of generated reverse braking force will be described later.

  The pulse-like signal is generated so that the amount of reverse braking force generated is within a range that does not cause overload to the vehicle 100 and unstable driving at the moment of generating the signal. May be input to the motors 10a and 10b to perform reverse braking. Also in this case, as a result, as shown in FIG. 5, the pulse-like signal is determined so as to increase stepwise.

FIG. 6 is a flowchart showing more specific control shown in FIG.
In addition, about the matter demonstrated along FIG. 4, description here shall be abbreviate | omitted suitably.

  When the brake depression degree detection sensor 92 detects that the depression degree of the brake pedal B is 100%, it is determined that the brake request is made by the ECU 90 (S21, S22). Here, the degree of depression of the brake pedal B for determining that a brake request has been made is not limited to 100%.

  When it is determined that a brake request has been made, the ECU 90 functioning as a braking control means drives the braking means 67 to start braking of the vehicle 100 (S23), based on the vehicle speed detected by the wheel rotation sensor 65 ( S24) The ECU 90 functioning as the braking degree determination means determines whether or not the braking degree by the braking means 67, in other words, the deceleration is normal within a predetermined determination time (S25).

  In step S25, if the deceleration is 0 or notably low, it is determined that the brake means 67 is not functioning normally (S26), and if not, the brake means 67 is normal. Assuming that it is functioning, the braking means 67 is driven as usual to brake the vehicle 100.

  If it is determined that the brake system is abnormal as shown in step S26, it is confirmed whether or not the brake request is continued (S27). If it is not continued, the control is terminated and continued. In that case, the regeneration control is started by the ECU 90 functioning as the regeneration control means (S28).

  When regenerative control is started as shown in step S28, it is checked whether or not the vehicle speed detected by the wheel rotation sensor 65 is decreasing (S29). If it is determined that the vehicle speed is decreasing, the SOC detection is performed. It is determined whether or not the battery voltage is detected by the means 94 near the upper limit (S30).

  If it is determined in step S30 that the battery voltage is not near the upper limit, the regeneration control started in step S28 is continued, and if it is determined in step S30 that the battery voltage is near the upper limit. Then, when regeneration is continued by the ECU 90 functioning as overcharge determination means, it is determined whether or not overcharge occurs.

  The determination of whether or not overcharge occurs includes determination of whether or not overcharge occurs when power is forcibly consumed by forced driving of the air conditioner 50 and the cooling fan (S31). If charging does not occur, forced consumption is started assuming that consumption is possible (S32), and the process returns to step S27 to check whether the brake request is continued.

  If it is determined in step S29 that the vehicle speed has not decreased, and if it is determined in step S31 that overcharging will occur even if the power is forcibly consumed, control of the ECU 90 that functions as reverse braking control means is performed. , Reverse braking is performed (S33).

  If reverse braking is performed, there is a burden on the vehicle 100 and concerns about the running posture. Therefore, it is inherently preferable to perform regenerative braking while avoiding reverse braking as much as possible. Therefore, in step S31, the determination of whether or not overcharging occurs also includes determination of whether or not overcharging occurs even when forced power consumption is performed. From the viewpoint of forced power consumption, it is preferable to provide a capacitor for forced power consumption. However, in order to avoid the high cost due to this capacitor, this embodiment does not include this.

  From the viewpoint of avoiding reverse braking as much as possible, braking by regeneration may be performed as much as possible while relaxing the degree of regeneration. Also in this case, it is desirable to avoid overcharging by forcibly consuming power.

  When reverse braking is started in step S33, the traveling posture of the vehicle 100 is stabilized based on the traveling state of the vehicle 100 detected by the ECU 90 functioning as the traveling state detecting unit by the ECU 90 functioning as the vehicle posture controlling unit. The control to be activated is started (S34).

  When the vehicle speed decreases due to reverse braking and the vehicle speed decreases to a predetermined speed at which braking by the side brake means 68 is performed (S35), braking by the side brake means 68 is started by the ECU 90 functioning as side brake control means (S36). ) When the vehicle speed becomes 0 km and the vehicle 100 stops (S37), the control is terminated.

  FIG. 7 shows a flowchart of an example of control for stabilizing the traveling posture of the vehicle 100 based on the traveling state of the vehicle 100 detected by the ECU 90 functioning as the traveling state detection unit, performed by the ECU 90 functioning as the vehicle posture control unit. Show.

  First, based on the values of the front wheel speed, rear wheel speed, and vertical G detected by each sensor, or in the configuration shown in FIG. 10, the front left and right wheel speeds, the rear left and right wheel speeds, and the lateral G Based on the value (S41), the ECU 90 functioning as the traveling state detecting means determines whether the traveling state of the vehicle 100 is the target longitudinal rotation difference, the target longitudinal G level range, or in the configuration shown in FIG. It is determined whether or not the difference is within the range of the target longitudinal / lateral rotation difference and the target lateral G level (S42).

  As a result of the determination in step S42, if the detected value is within such a range, the flag is not set, and the ECU 90 functioning as the vehicle attitude control means does not perform control for stabilizing the traveling attitude of the vehicle 100, and has already been described. As described above, it is determined whether or not the vehicle speed is decreasing (S43). If the vehicle speed is decreasing, it is determined whether or not the vehicle is stopped (S44). Exit.

  If the result of determination in step S42 is that the detected value is not within this range, a positive or negative flag is set, reverse braking is performed under the control of the ECU 90 functioning as reverse braking control means, and vehicle attitude control means. The ECU 90 that functions as a control for stabilizing the traveling posture of the vehicle 100 is performed (S45). Even in such a case, it is assumed that the conditions for performing reverse braking under the control of the ECU 90 functioning as reverse braking control means are satisfied.

  If the result of determination in step S43 is that the vehicle speed has not decreased, reverse braking is performed under the control of the ECU 90 functioning as reverse braking control means without setting a flag (S45).

  In step S45, reverse braking by generation of reverse torque for the front wheels using reverse rotation of the motor 10a using detected values by the sensors including the steering angle sensor 91 and the wheel rotation sensor 65 functioning as a vehicle speed sensor, In addition to this, in the configuration shown in FIG. 10, reverse braking by generating reverse torque using reverse rotation of the right motors 10a and 10b (S45a), and generation of reverse torque for rear wheels using reverse rotation of the motor 10b. In the configuration shown in FIG. 10, in addition to this, the reverse braking by the generation of the reverse torque using the reverse rotation of the left motors 10a and 10b (S45b) is performed while appropriately adjusting. For example, the reverse rotation control of the motors 10a and 10b is performed while optimizing with appropriate values by alternation, synchronization, cooperation and the like.

  Whether the flag is positive or negative is determined by, for example, a target front-rear rotation in which the front-rear wheel rotation difference detected by each sensor and the vertical G value are target values, as described in a square frame in FIG. What deviation is taken with respect to the difference and the target vertical G level, and in addition to this, in the configuration shown in FIG. It is done depending on whether or not.

  For example, the front / rear wheel rotation difference is detected as a difference between the front wheel and rear wheel rotation sensors 65 by the ECU 90 functioning as the front / rear wheel rotation difference detecting means, as shown in FIG. Control is performed on reverse braking by the motors 10a and 10b to stabilize the traveling posture of the vehicle 100, which is input to the ECU 90 that functions as vehicle posture control means in comparison with the rotation difference.

  Then, the ECU 90 functioning as the reverse braking control means, when the front-rear wheel rotation difference detected by the ECU 90 functioning as the front-rear wheel rotation difference detection means exceeds a predetermined front-rear wheel rotation difference target value that is the target front-rear rotation difference. The reverse braking force by the motors 10a and 10b is varied independently to adjust and vary the amount of reverse braking force generated so that the front and rear wheel rotational difference becomes the front and rear wheel rotational difference target value.

  Further, the ECU 90 functioning as the reverse braking control means, when the longitudinal G detected by the ECU 90 functioning as the longitudinal gravity detecting means, that is, the longitudinal gravity exceeds a predetermined longitudinal gravity target value that is the target longitudinal G level, the motor 10a. By varying the reverse braking force by 10b independently, the amount of reverse braking force generated is adjusted and varied so that the longitudinal gravity becomes the longitudinal gravity target value.

  In this way, as shown in FIG. 8, in order to perform reverse braking by the motors 10a and 10b, the pulse widths and torques of the signals input to these are appropriately set and generated by the motors 10a and 10b. The reverse torque is adjusted. As shown in the figure, the pulse width and the torque are controlled individually or in combination.

The value of the reverse torque due to reverse braking is determined by the ECU 90 functioning as reverse braking control means and / or vehicle attitude control means according to the vehicle weight, vehicle speed, and the like.
An example of this is shown in FIG. As shown in the figure, this determination is roughly made through a base axle weight calculation method and a torque / pulse width calculation performed subsequently.

  First, the axle weight calculation method for each base will be described. The ECU 90 functioning as the reverse braking control means and / or the vehicle attitude control means is based on the vehicle weight and the leveling sensor coefficient on each side of the front and rear wheels. As shown in the upper graph, the base weight of each side is calculated.

  Next, the calculation of torque and pulse width will be described. The ECU 90 functioning as reverse braking control means and / or vehicle attitude control means, based on the base weight and the vehicle attitude coefficient on the respective front and rear wheels sides. As shown in the lower graph, the weight of each side is calculated and input to the ECU 90 functioning as the reverse braking control means and / or the vehicle attitude control means together with the detection values of the respective sensors. .

  The ECU 90 functioning as reverse braking control means and / or vehicle attitude control means has a vehicle speed / weight-torque base MAP, vehicle speed / torque-pulse width base MAP, vehicle speed / pulse width-OFF pulse width stored in its memory. Based on the MAP, a torque base, a pulse width base, and the like are acquired using each detected value such as the input weight and vehicle speed.

  Next, the ECU 90 functioning as the reverse braking control means and / or the vehicle attitude control means, based on the vertical G level torque-Δ deviation MAP stored in the memory, the already acquired torque base, the input vertical G A Δtorque deviation 1 and a Δpulse width 1 are acquired using each detected value such as a level and a steering angle. In this case, in the configuration shown in FIG. 10, the ECU 90 functioning as the reverse braking control means and / or the vehicle attitude control means stores the longitudinal G level torque-Δ deviation MAP, front and rear wheels, stored in its memory. Based on the respective lateral G level / steering angle sensor / torque-Δ deviation MAP, the detected torque base, input vertical G level, lateral G level, steering angle, etc. are used to obtain Δ torque deviation. 1 to 3 and Δ pulse widths 1 to 3 are acquired.

  Then, the ECU 90 functioning as the reverse braking control means and / or the vehicle attitude control means acquires the reverse torque value based on the acquired torque base and the Δ torque deviation 1 or the Δ torque deviation 1 to 3, and the acquired pulse. The pulse width is acquired based on the width base and Δpulse width 1 or Δpulse widths 1 to 3. These reverse torque values and pulse widths are, for example, the signal waveforms shown in FIG.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the specific embodiments, and the present invention described in the claims is not specifically limited by the above description. Various modifications and changes are possible within the scope of the above.

For example, the electric vehicle to which the present invention is applied is not limited to an electric vehicle (EV), but may be a plug-in hybrid vehicle (PHEV), a hybrid vehicle (HEV), or the like.
The electric vehicle may be provided with a driving motor that drives either the front wheel or the rear wheel as a driving wheel, and the other wheel as a driven wheel.

Further, as shown in FIG. 10, the vehicle may be a vehicle in which left and right wheels of the vehicle front wheel or rear wheel are driven by separate left and right motors, for example, in-wheel motors. The reverse braking force of the motor and the right motor may be adjusted.
The brake member is not limited to a brake pedal operated with a leg, but may be a manual brake operated with a hand.

  The effects described in the embodiments of the present invention are only the most preferable effects resulting from the present invention, and the effects of the present invention are limited to those described in the embodiments of the present invention. is not.

10a, 10b Traveling motor, regenerative braking means 10a Front wheel motor 10b Rear wheel motor 20 Battery 30a, 30b Regenerative charging means 62 Front wheel 64 Rear wheel device 65 Vehicle speed detection means 67 Braking means 68 Side brake means 90 Vehicle attitude detection means, traveling state Detection means, control means, calculation means, longitudinal wheel rotation difference detection means, vertical gravity detection means, regenerative charge availability determination means, hydraulic brake device abnormality detection means 92 brake pedal depression amount detection means 94 battery state detection means 100 vehicle B brake pedal

Claims (6)

A vehicle that travels forward when a torque is generated in the forward rotation direction of the traveling motor,
Vehicle speed detection means for detecting the vehicle speed of the vehicle;
Vehicle attitude detection means for detecting the attitude of the vehicle;
Traveling state detection means for detecting the traveling state of the vehicle from the vehicle speed and posture of the vehicle;
Control means for generating reverse braking force by intermittently generating torque in the reverse rotation direction of the traveling motor,
Wherein said control means includes calculating means for calculating a maximum generation amount of the reverse braking force necessary to stop the previous SL wheel cars, the reverse braking force based on the running state detected by the traveling state detecting means amount with variable generation, car both you and characterized by increasing the generation amount stepwise until the maximum generation amount. The vehicle posture detection means includes front and rear wheel rotation difference detection means for detecting a rotation difference between front and rear wheels of the vehicle,
2. The control device according to claim 1, wherein when the rotation difference exceeds a predetermined front and rear wheel rotation difference target value, the control unit varies the generated amount so as to become the predetermined front and rear wheel rotation difference target value. The vehicle described. The vehicle posture detection means has vertical gravity detection means for detecting vertical gravity applied to the front and rear of the vehicle,
The said control means varies the said generation amount so that it may become the said predetermined | prescribed vertical gravity target value, when the said longitudinal gravity exceeds a predetermined vertical gravity target value. vehicle. A battery for supplying power to the driving motor;
Regenerative braking means by the traveling motor;
Regenerative charging means for charging the battery by the regenerative braking means;
Battery state detection means for detecting the state of charge of the battery;
Regenerative charge availability determination means for determining whether regenerative charge is possible based on the battery charge state and the running state;
The vehicle according to any one of claims 1 to 3, wherein the control means generates the reverse braking force when the regenerative charge availability determination means determines that regenerative charge is impossible. A hydraulic braking device;
Brake pedal depression amount detection means for detecting the depression amount of the brake pedal,
Hydraulic braking device abnormality detecting means for detecting abnormality of the braking device based on the depression amount and the vehicle speed of the vehicle;
The vehicle according to any one of claims 1 to 4, wherein the control means generates the reverse braking force when the abnormality is detected. The travel motor comprises a front wheel motor that drives a front wheel of the vehicle and a rear wheel motor that drives a rear wheel,
The vehicle according to any one of claims 1 to 5, wherein the control means varies the generation amount of each of the front wheel motor and the rear wheel motor.

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