JP2007008334A - Braking control unit of vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a braking control unit which can suppress variations in braking force, caused by a change in the weight of a vehicle, by accurately computing the weight of the vehicle, without newly providing a special device or a sensor. <P>SOLUTION: This braking control unit of the vehicle controls a braking force, imparted to a wheel, by controlling brake fluid pressure in a wheel cylinder, depending on a driver's braking operation. The braking control unit comprises: an energy detecting means (block B21) for detecting energy output by a driving force source; a vehicle-speed variation detecting means (block B22) for detecting the variation of the speed of the vehicle; a first vehicle-weight computing means (block B23) for computing the weight of the vehicle on the basis of the energy detected by the energy detecting means, and the variation of the speed of the vehicle, detected by the vehicle-speed variation detecting means; and braking-force setting means (blocks B20 and B30) for setting the braking force larger as the weight of the vehicle, computed by the first vehicle-weight computing means, becomes larger. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vehicle braking control device that controls braking force applied to wheels based on a driver's braking operation.

  In recent years, a braking control device (electronic control brake system) that electrically controls a braking device that applies braking force to wheels has been developed as a device that controls the braking force of a vehicle. In such an electronically controlled brake system, vehicle information such as a driver's braking request (for example, the amount of operation of a brake pedal), wheel speed, vehicle weight, and the like is detected, and a target reduction is performed based on the detected value of each vehicle information. The speed is set, and the braking force of the vehicle is controlled by adjusting the hydraulic pressure (brake hydraulic pressure) supplied to the wheel cylinder of the braking device with respect to the target deceleration. An example of an invention related to such a braking control device is described in Patent Document 1.

  According to the braking control device described in Patent Document 1, a target deceleration is set from the occupant's braking operation amount, a deceleration generated in the vehicle is detected, and a reference value corresponding to the target deceleration is obtained. A braking command value is set from the correction amount corresponding to the deceleration, and the braking force to each wheel is controlled. Then, the loaded weight or the vehicle weight is detected, and the gain with respect to the target deceleration of the reference value increases as the loaded weight or the vehicle weight increases. Therefore, for example, even when the deceleration of the vehicle cannot be detected correctly due to disturbance, appropriate braking force control can be executed, and even when the load weight or the vehicle weight fluctuates, the braking force is set to an appropriate range. It is supposed to be possible.

Further, in Patent Document 2, the output shaft torque of the automobile is estimated from the vehicle speed and the engine speed, and from the estimated output shaft torque, the acceleration detected by the means for detecting the acceleration, and the vehicle speed, An invention relating to an output shaft torque estimating device and a vehicle weight calculating device of an automobile configured to obtain the vehicle weight is described.
JP 2003-335233 A JP-A-6-201523

  The braking control device described in Patent Document 1 is configured such that a deceleration acting on the vehicle is detected, and the braking force is feedback-controlled based on the detected vehicle deceleration, The vehicle deceleration detected in this case is calculated on the basis of the rotational speed of the drive wheels and the loaded weight (vehicle weight). At this time, for example, if the vehicle weight is set uniformly or the vehicle weight detection accuracy is low, and the vehicle deceleration is not detected accurately, the vehicle braking force varies, and the appropriate braking force Control cannot be executed. As a result, there is a variation in the effectiveness of the brake, and the driver may feel that the brake is not effective, or the brake may be too effective and difficult to operate. Therefore, in the invention described in Patent Document 1, the wheel suspension is provided with a stroke sensor for detecting the stroke value, and the vehicle weight is estimated based on the detected value of the stroke sensor. ing.

  However, when the vehicle weight is estimated using the stroke value of the suspension of each wheel as in the braking control device described in Patent Document 1, it is necessary to install a stroke sensor on each wheel. Furthermore, in order to accurately estimate the vehicle weight by the stroke sensor even on an inclined road surface, for example, an inclination angle sensor or the like is separately required. Thus, in order to obtain the vehicle weight with high accuracy, a sensor or device such as a stroke sensor or an inclination angle sensor has to be newly installed separately.

  In addition, the vehicle weight calculation device described in the above-mentioned Patent Document 2 aims to obtain the vehicle weight without newly providing a special sensor, and the vehicle weight is calculated from at least the output shaft torque, acceleration, and vehicle speed. Is configured to be estimated. However, there is a possibility that the detection accuracy of the vehicle speed detected using the speed sensor and the acceleration calculated from the vehicle speed may be reduced due to the influence of disturbances and the like, and therefore the estimation accuracy of the vehicle weight may be reduced. there were.

  The present invention has been made paying attention to the above technical problem, and accurately calculates the vehicle weight without newly installing a special device or sensor, and sets the braking force based on the calculation result. Thus, an object of the present invention is to provide a braking control device for a vehicle that can suppress the degree of braking effectiveness, that is, variation in braking force, caused by a change in vehicle weight.

  In order to achieve the above object, a first aspect of the present invention is a vehicle braking control apparatus for controlling a braking force applied to a wheel by controlling a brake fluid pressure in a wheel cylinder in accordance with a braking operation of a driver. The energy detection means for detecting the energy output from the driving force source, the vehicle speed change amount detection means for detecting the change amount of the vehicle speed, and the energy detected by the energy detection means and the vehicle speed change amount detection means. First vehicle weight calculating means for calculating vehicle weight based on the change amount of the vehicle speed, and braking force setting means for setting the braking force to be larger as the vehicle weight calculated by the first vehicle weight calculating means is larger. It is provided with the control apparatus characterized by these.

  According to a second aspect of the present invention, in the first aspect of the present invention, the temperature detecting means for detecting the temperature of the driving force source, the driving force detecting means for detecting the driving force of the driving force source, and the front and rear of the vehicle Acceleration detecting means for detecting acceleration; and second vehicle weight calculating means for calculating vehicle weight based on the driving force detected by the driving force detecting means and the longitudinal acceleration detected by the acceleration detecting means. The braking force setting means uses the vehicle weight calculated by the second vehicle weight calculating means when the temperature of the driving force source detected by the temperature detecting means is outside a predetermined temperature range. The control device includes means for setting the braking force.

  Further, the invention of claim 3 is the invention of claim 1 or 2, wherein the braking force setting means is calculated by the vehicle weight calculated by the first vehicle weight calculation means and the second vehicle weight calculation means. The control apparatus includes means for setting the braking force using a larger one of the vehicle weight and the vehicle weight.

  Furthermore, the invention of claim 4 further comprises a driving environment detecting means for detecting a driving environment of the vehicle according to any one of the first to third aspects, wherein the braking force setting means is the driving environment detecting means. A control device comprising: means for setting the braking force based on the traveling environment detected by the vehicle.

  A fifth aspect of the present invention is the control device according to any one of the first to fourth aspects, wherein the driving force source is a motor or a motor generator.

  According to the first aspect of the invention, the energy output from the driving force source and the amount of change in the vehicle speed are detected, and the vehicle weight is calculated by the first vehicle weight calculation means based on the detected values. This generally utilizes the fact that the amount of increase in vehicle speed relative to the energy output from the driving force source decreases as the vehicle weight increases. For example, the vehicle can be used without specially using a load sensor, an acceleration sensor, or a stroke sensor. The weight can be obtained with high accuracy. Since the braking force applied to the wheels increases as the vehicle weight calculated by the first vehicle weight calculation means increases, variation in the effectiveness of the brake is prevented or suppressed, and an appropriate size is achieved. The vehicle can be reliably braked with the braking force.

  According to the invention of claim 2, the temperature of the driving force source, the driving force of the driving force source, and the acceleration of the vehicle are detected, and the second is based on the detected value of the driving force and the detected value of the acceleration. The vehicle weight is calculated by the vehicle weight calculation means. In general, this utilizes the fact that the longitudinal acceleration with respect to the driving force decreases as the vehicle weight increases. For example, the vehicle weight can be accurately obtained without specially using a load sensor or a stroke sensor. . Then, when the temperature of the driving force source is outside a predetermined temperature range determined as a temperature range in which the driving force source is stably operated, the vehicle weight calculated by the second vehicle weight calculating means is adopted. Then, the braking force applied to the wheels is controlled to increase as the vehicle weight calculated by the second vehicle weight calculating means increases. For example, in a state where the driving force source is not stable, such as immediately after starting, the energy output from the driving force source cannot be detected accurately, and the vehicle weight estimation accuracy by the first vehicle weight calculating unit may be reduced. In this case, since the braking force is controlled by using the vehicle weight calculated by the second vehicle weight calculating means, it is possible to ensure the estimation accuracy of the vehicle weight and perform appropriate braking force control.

  Further, according to the invention of claim 3, the vehicle weight calculated by the first vehicle weight calculating means is compared with the vehicle weight calculated by the second vehicle weight calculating means, and the larger vehicle weight is adopted. The braking force applied to the wheels is controlled to increase as the vehicle weight increases. Therefore, a larger braking force is set as compared with the case where the braking force is set based on the smaller vehicle weight, and the vehicle can be braked more reliably.

  Furthermore, according to the invention of claim 4, for example, a traveling environment such as a road surface inclination angle, a road surface friction coefficient, or air resistance is detected, and the braking force applied to the wheel is set in consideration of the traveling environment. Therefore, more appropriate braking force control can be performed.

  According to the fifth aspect of the present invention, for a vehicle having a motor or motor / generator as a driving force source, variation in the effectiveness of the brake is prevented or suppressed, and the vehicle is reliably secured with an appropriate magnitude of braking force. Can be braked.

  Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 3 schematically shows a configuration (hydraulic pressure system) of a braking device 1 for a vehicle to which the present invention is applied. The braking device 1 uses a hydraulic pressure (brake hydraulic pressure) generated by a master cylinder 2. The normal braking control for braking by supplying to the wheel cylinders 3, 4, 5, 6 provided for each wheel according to the driver's braking operation and the brake fluid pressure stored in the accumulator etc. It is configured to be able to execute braking control by an electronically controlled brake system that is electrically controlled according to a braking operation and supplied to the wheel cylinders 3, 4, 5, and 6 of each wheel.

  First, a description will be given of a first hydraulic system that supplies brake hydraulic pressure to the wheel cylinders 3, 4, 5, and 6 from the master cylinder 2 when normal braking control is performed. The master cylinder 2 is mechanically connected to, for example, a brake pedal 7 operated by a driver, and is configured such that the brake fluid pressure is increased by an operating force (stepping force) applied to the brake pedal 7. The master cylinder 2 is provided with two independent pressure chambers 2f and 2r. Of these, the pressure chamber 2f has a normally open type (type that closes when energized) on-off valve 8 in the middle of the pipeline. One end of a hydraulic pipe 9 provided with is connected, and the other end of the hydraulic pipe 9 is connected to a wheel cylinder 3 constituting a braking mechanism for the left front wheel. The wheel cylinder 4 constituting the braking mechanism for the right front wheel has a hydraulic pipe 9 between the electromagnetic on-off valve 8 and the wheel cylinder 3 by a hydraulic pipe 11 provided with a normally open type on-off valve 10 in the middle of the pipeline. It is connected to the.

  On the other hand, one end of a hydraulic pipe 13 having a normally open type on-off valve 12 is connected to the pressure chamber 2r in the middle of the pipeline, and the other end side of the hydraulic pipe 13 is a braking mechanism for the left rear wheel. Is connected to a wheel cylinder 5 constituting the. Further, the wheel cylinder 6 constituting the braking mechanism for the right rear wheel has a hydraulic pipe 13 between the on-off valve 12 and the wheel cylinder 5 by a hydraulic pipe 15 provided with a normally open type on-off valve 14 in the middle of the pipeline. It is connected to the. Therefore, when the on / off valves 8, 10, 12, and 14 are not energized, the brake fluid pressure in the pressure chamber 2f of the master cylinder 2 is supplied to the wheel cylinders 3 and 4 on the front wheel side, and the pressure chamber 2r. The brake hydraulic pressure is supplied to the wheel cylinders 5 and 6 on the rear wheel side.

  That is, a hydraulic system that connects the pressure chamber 2 f and the wheel cylinders 3 and 4 via the hydraulic pipes 9 and 11, and a fluid that connects the pressure chamber 2 r and the wheel cylinders 5 and 6 via the hydraulic pipes 13 and 15. The first pressure system supplies the master cylinder pressure to each of the wheel cylinders 3, 4, 5, 6 when braking control by an electronically controlled brake system, which will be described later, is not performed, that is, when normal braking control is performed. This constitutes the hydraulic system.

  Next, the brake fluid pressure is supplied to the wheel cylinders 3, 4, 5 and 6 when the brake control is executed by the electronically controlled brake system which electrically adjusts the wheel cylinder pressure in accordance with the driver's braking operation. A second hydraulic system for performing the above will be described. A hydraulic pressure pipe 17 whose one end is connected to the reservoir 16 is provided with a hydraulic pressure pump 19 driven by a motor 18 in the middle of the pipeline, and the hydraulic fluid flowing from the reservoir 16 is pressurized by the hydraulic pressure pump 19. It is the composition which becomes. An accumulator 21 for accumulating high-pressure hydraulic fluid discharged from the hydraulic pump 19 is connected to the hydraulic pipe 20 on the discharge side of the hydraulic pump 19.

  The hydraulic pipe 20 on the downstream side of the accumulator 21 has a normally closed type (a type that opens when energized) that can linearly control the valve opening according to the magnitude of the input control signal. , 23, 24, 25 are connected to the downstream sides of the control valves 22, 23, 24, 25, respectively. Each of the hydraulic pipes 26, 27, 28, 29 is branched into two, and one of the branch pipes 30, 31, 32, 33 is connected to the wheel cylinders 3, 4, 5, 6 respectively. . The other branch pipes 34, 35, 36, and 37 are connected to a hydraulic pipe 42 having one end connected to the reservoir 16 via a normally closed control valve 38, 39, 40, and 41, respectively.

  The hydraulic circuit is provided with a pressure sensor for detecting the brake hydraulic pressure in each part of the hydraulic circuit. That is, a master cylinder pressure sensor 51 that detects the brake fluid pressure of the portion as a master cylinder pressure is provided in the hydraulic pressure tube 9 between the pressure chamber 2 f of the master cylinder 2 and the on-off valve 8. The hydraulic pipe 20 connected to the accumulator 21 is provided with an accumulator pressure sensor 52 that detects the brake hydraulic pressure in this portion as the accumulator pressure. Further, wheel cylinder pressure sensors 53, 54, 55, 56 for detecting the brake fluid pressure of the portions as the respective wheel cylinder pressures are provided in the pipe lines near the respective wheel cylinders 3, 4, 5, 6. Yes.

  The operation of the second hydraulic system constructed as described above will be briefly described. First, the on-off valves 8 and 12 are controlled to be closed, and the wheel cylinders 3, 4, 5, The supply of brake fluid pressure to 6, that is, the supply of brake fluid pressure by the first fluid pressure system is shut off, and the on-off valves 10, 14 are controlled to be closed so that each wheel cylinder 3, 4, 5 , 6 can be controlled independently of the brake fluid pressure. That is, the hydraulic pressure supply system to each wheel cylinder 3, 4, 5, 6 is switched from the first hydraulic system described above to the second hydraulic system. As described above, the first hydraulic system and the second hydraulic system are configured to be connected to the wheel cylinders 3, 4, 5, and 6 in an exclusive relationship with each other.

  When the pressure increase control for increasing the brake fluid pressure of the wheel cylinders 3, 4, 5, 6 is executed, the control valves 38, 39, 40, 41 functioning as pressure reduction control valves are closed and increased. The valve openings of the control valves 22, 23, 24, and 25 that function as pressure control valves are controlled. Thus, the high-pressure hydraulic fluid in the accumulator 21 is sequentially passed through the hydraulic pipe 20, the control valves 22, 23, 24, 25, the hydraulic pipes 26, 27, 28, 29, and the branch pipes 30, 31, 32, 33. Is supplied to each of the wheel cylinders 3, 4, 5, and 6, so that the wheel cylinder pressure is increased.

  On the other hand, at the time of execution of pressure reduction control for reducing the brake fluid pressure of the wheel cylinders 3, 4, 5, 6, the control valves 22, 23, 24, 25 are closed and the control valves 38, 39, 40, 41 are closed. The valve opening is controlled. As a result, the hydraulic fluid in each of the wheel cylinders 3, 4, 5, 6 is supplied to the branch pipes 30, 31, 32, 33, branch pipes 34, 35, 36, 37, control valves 38, 39, 40, 41, hydraulic pipes. Since the exhaust gas is discharged to the reservoir 16 side through 42 in order, the wheel cylinder pressure is reduced.

  Further, by closing the control valves 22, 23, 24, 25 and the control valves 38, 39, 40, 41, the brake fluid pressures of the wheel cylinders 3, 4, 5, 6 are kept constant. It can also be held.

  When the braking control by the electronic control brake system is executed as described above, the operation of the braking device 1 is controlled by the electronic control device 100 shown in FIG. In other words, the electronic control device 100 controls the operation of each on-off valve 8, 10, 12, 14 and each control valve 22, 23, 24, 25, 38, 39, 40, 41 of the braking device 1, and each wheel cylinder. The brake fluid pressure in 3, 4, 5, 6 is controlled to increase or decrease. Therefore, calculation processing is performed in the electronic control unit 100 in accordance with the driver's braking operation, and the braking force applied to each wheel is set by the control signal output based on the calculation processing result. In other words, the electronic control unit 100 controls the braking force applied to each wheel by controlling the brake fluid pressure in each of the wheel cylinders 3, 4, 5, and 6 in accordance with the driver's braking operation.

  FIG. 4 schematically shows a configuration of the electronic control device 100 and a control system used in the control device of the present invention. The electronic control unit 100 includes a master cylinder pressure sensor 51 that detects the aforementioned master cylinder pressure, an accumulator pressure sensor 52 that detects the accumulator pressure, and wheel cylinder pressure sensors 53, 54, 55, and 56 that detect the wheel cylinder pressures, respectively. , Wheel speed sensors 101, 102, 103, 104 for detecting the rotation speed (rotation speed, rotation direction) of each wheel, brake pedal sensor (or brake pedal) for detecting the depression amount (stroke) or depression pressure of the brake pedal 7 Various sensors such as a stroke sensor) 105, a longitudinal acceleration sensor 106 for detecting the longitudinal acceleration of the vehicle, and a temperature sensor 107 for detecting the temperature of the driving force source P of the vehicle are provided, and output signals of these sensors are provided. Is input to the electronic control unit 100. It has been made.

  In addition, various data relating to the operating state or control state of the driving force source P is input to the electronic control unit 100. Here, as the driving force source P of the vehicle, for example, at least one of an internal combustion engine or an electric motor can be used. As the internal combustion engine, for example, an internal combustion engine having a mechanism capable of electrically controlling the output of an electronic throttle valve or the like. Institution is used. As an electric motor, in addition to a normal motor that generates driving torque by supplying electric power, for example, a motor generator having a power running function that converts electrical energy into kinetic energy and a regeneration function that converts kinetic energy into electrical energy. It is possible to use. In this embodiment, a case where a motor M is used as the driving force source P will be described.

  Therefore, the electronic control unit 100 includes the output, energy, and drive of the motor M obtained from the motor control data such as the amount of electric power, current, and voltage supplied to the driving force source P, that is, the motor M, or the motor control data. A value such as torque is input. Various types of data are stored in the electronic control device 100. Based on a signal input to the electronic control device 100 and the stored data, the electronic control device 100 can transmit the vehicle braking device 1 and A signal for controlling the driving force source P is output.

  Here, the electronic control device 100 performs arithmetic processing based on the detected values of the rotational speeds of the wheels detected by the wheel speed sensors 101, 102, 103, and 104, respectively. Can be detected. Therefore, the electronic control unit 100, the wheel speed sensors 101, 102, 103, 104, etc. function as vehicle speed change amount detecting means in the present invention.

  Further, the electronic control device is based on the detected values such as the rotational speed and rotational direction of each wheel detected by each wheel speed sensor 101, 102, 103, 104, or the longitudinal acceleration of the vehicle detected by the longitudinal acceleration sensor 106. By performing arithmetic processing at 100, the longitudinal acceleration state of the vehicle can be detected. Therefore, the electronic control unit 100, the wheel speed sensors 101, 102, 103, 104, the longitudinal acceleration sensor 106, etc. function as the acceleration detecting means of the present invention. Note that the longitudinal acceleration of the vehicle can be obtained only from the detection values obtained by the wheel speed sensors 101, 102, 103, and 104 without using the longitudinal acceleration sensor 106 described above.

  The electronic control device is based on detected values such as the rotational speed and rotational direction of the wheels detected by the wheel speed sensors 101, 102, 103, and 104, or the longitudinal acceleration of the vehicle detected by the longitudinal acceleration sensor 106. By performing arithmetic processing at 100, it is possible to detect or estimate the traveling environment of the vehicle such as the inclination angle and friction coefficient of the road surface on which the vehicle is traveling, or the air resistance that the vehicle receives during traveling. Therefore, the electronic control device 100, the wheel speed sensors 101, 102, 103, 104, the longitudinal acceleration sensor 106, and the like function as the traveling environment detection means of the present invention.

  As described above, the present invention accurately estimates the vehicle weight without newly providing a special sensor or device, thereby reducing variations in braking force due to changes in vehicle weight, that is, variations in brake effectiveness. For this purpose, the control device of the present invention is configured to execute control as follows.

  FIG. 1 is a block diagram for explaining an example of control by the control device of the present invention. First, the target deceleration Gt is calculated and set in accordance with a braking operation by the driver such as a depression operation of the brake pedal 7 (block B10). Specifically, as the amount of braking operation by the driver, the master cylinder pressure that is increased according to the depression operation of the brake pedal 7 or the depression of the brake pedal 7 by, for example, the brake pedal sensor (brake pedal stroke sensor) 105 or the like. A deceleration is set as a target deceleration Gt to be obtained when a stroke is detected, a calculation process is performed based on the detected value, and a braking force set according to a braking operation amount at that time is applied to the wheel. Is done.

  And the vehicle weight W considered when setting the braking force of a vehicle is set (block B20). The braking force of the vehicle varies depending on the vehicle weight at the time of braking, the friction coefficient between the brake rotor and the brake pad, or the conditions such as the inclination angle of the traveling road surface. If the magnitude of the braking force, that is, the effectiveness of the brakes, varies with respect to the driver's prescribed braking operation, the driver feels that the braking effect has deteriorated, or that the braking has become excessively effective. It feels difficult. Therefore, for example, if the estimation accuracy of the vehicle weight is deteriorated among the above conditions, the variation in the braking force is increased with respect to a predetermined braking operation, and drivability is lowered. Therefore, in this block B20, in order to accurately estimate the vehicle weight W, the vehicle weight is calculated as follows.

  That is, the vehicle weight W is estimated as the estimated vehicle weight Wa and the estimated vehicle weight Wb, respectively, by the following two arithmetic processes. Any one of the estimated vehicle weights Wa and Wb is appropriately selected and set as the vehicle weight W according to the state of the vehicle.

(First vehicle weight calculation control)
The first vehicle weight calculation control is control for calculating the estimated vehicle weight Wa from the output energy of the motor M, Em, and the vehicle speed V. First, the output energy Em of the motor M is calculated (block B21). Specifically, the output energy Em is the product of the current i and the voltage e when the motor M is controlled to rotate for a predetermined time Δt, that is, the output Pm (= η · i · e; η of the motor M). Is obtained by integrating the motor efficiency in the range of Δt.

Further, a change amount ΔV of the vehicle speed between the current vehicle speed V and the predetermined time Δt is obtained (block B22). Then, the kinetic energy Ek of the vehicle is calculated based on the output energy Em and the change amount ΔV of the vehicle speed, and the estimated vehicle weight Wa is calculated from the kinetic energy Ek and the vehicle speed V (block B23). That is, how much the output energy Em output from the motor M is converted into the kinetic energy Ek of the vehicle is obtained by calculation. Specifically, based on the change amount ΔV of the vehicle speed, for example, correction is performed in consideration of loss due to vehicle running resistance, brake loss, power loss of each part of the drive system, auxiliary load, etc., and kinetic energy Ek is calculated. The Based on the kinetic energy Ek and the vehicle speed V, the estimated vehicle weight Wa is
Wa = 2 · Ek / V ²
Is calculated as

(Second vehicle weight calculation control)
The second vehicle weight calculation control is control for calculating the estimated vehicle weight Wb from the driving torque Tm of the motor M and the longitudinal acceleration α of the vehicle. First, the drive torque Tm of the motor M is calculated (block B25). The driving torque Tm of the motor M can be obtained as a value proportional to the current value of the motor M. For example, when the rotational speed per unit time of the motor M is Nm,
Tm = Pm / (0.1047 · Nm)
Can be obtained as

Further, the longitudinal acceleration α of the vehicle is obtained, for example, by calculating as a detected value of the longitudinal acceleration sensor 106 or based on the detected values of the wheel speed sensors 101, 102, 103, 104 (block B26). Then, the estimated vehicle weight Wb is calculated from the driving force Fm of the motor M obtained by multiplying the driving torque Tm by the wheel radius and the vehicle longitudinal acceleration α (block B27). That is, the estimated vehicle weight Wb is
Wb = Fm / α
Is calculated as

  The above vehicle weight calculation control shows an example in which the driving force source P of the vehicle is the motor M. However, even if the driving force source P is an engine, the present invention is similarly applied. The control by can be applied. In this case, for example, the engine driving torque Te is the engine operating state such as the engine intake air amount, rotational speed, ignition timing, variable valve timing angle, torque converter torque ratio, engine friction or auxiliary load. And the like. Further, the engine output Pe can be obtained by multiplying the engine drive torque Te by the engine rotational speed Te, and the engine energy Ee can be obtained by multiplying the output Pe by a predetermined time Δt, Similarly, the estimated vehicle weights Wa and Wb can be calculated.

  Further, the control according to the present invention can be similarly applied to a hybrid vehicle including an engine and a motor / generator as the driving force source P. That is, in the hybrid vehicle, the power from the engine and the power from the motor / generator are appropriately distributed according to the traveling state and output as driving force, but the motor M and engine calculated as described above are used. The estimated vehicle weights Wa and Wb can be calculated in the same manner by appropriately distributing or selecting the output energy, output, and driving torque.

  When the estimated vehicle weights Wa and Wb are respectively calculated as described above, in the control in the block B20, the estimated vehicle weight Wa and the estimated vehicle weight Wb are compared, and the operating state of the motor M or the estimated vehicle weight Wa is compared. One of the estimated vehicle weights Wa and Wb is selected and set as the vehicle weight W to be considered when setting the braking force of the vehicle based on the comparison result of the magnitude with the estimated vehicle weight Wb.

Specifically, the vehicle weight W is set according to the procedure shown in the flowchart of FIG. First, it is determined whether or not the temperature Hm of the motor M detected by the temperature sensor 107 is within a predetermined temperature range (step S1). The predetermined temperature range is a temperature range predetermined as a temperature at which the motor M can be operated normally and stably. For example, in the case of a general motor, a temperature of about 60 ° C. to about 90 ° C. Set as a range. That is, in step S1, if the upper limit temperature of the temperature range in which the motor M can be operated normally and stably is Um and the lower limit temperature is Lm, the motor temperature Hm is
Lm ≦ Hm ≦ Um
It is determined whether or not the temperature is within a temperature range that satisfies the above.

  If the motor temperature Hm is not within the predetermined temperature range, that is, if the motor temperature Hm is lower than the lower limit temperature Lm or the motor temperature Hm is higher than the upper limit temperature Um, a negative determination is made in this step S1. Proceeding to S2, the estimated vehicle weight Wb is selected and set as the vehicle weight W.

  The estimated vehicle weight Wa calculated based on the output energy Em of the motor M and the vehicle speed V is relatively easily affected when the driving state of the motor M fluctuates. That is, for example, when the motor M has not yet stabilized and the motor temperature Hm has not reached the predetermined temperature range, such as immediately after starting, the accuracy in obtaining the output energy Em decreases, and the vehicle weight is estimated. Accuracy may be reduced. Therefore, when the motor temperature Hm is detected and the detected value of the motor temperature Hm is not within the predetermined temperature range, the estimated vehicle weight Wb is selected as the vehicle weight W considered when setting the braking force of the vehicle. Thus, the estimation accuracy of the vehicle weight can be ensured.

  On the other hand, if the motor temperature Hm is within the predetermined temperature range and the determination in step S1 is affirmative, the process proceeds to step S3 where the estimated vehicle weight Wa and the estimated vehicle weight Wb are compared, It is determined whether or not the estimated vehicle weight Wa is larger than the estimated vehicle weight Wb. When the estimated vehicle weight Wa is equal to or less than the estimated vehicle weight Wb, if a negative determination is made in step S3, the process proceeds to step S2, and the estimated vehicle weight Wb is selected and set as the vehicle weight W. On the other hand, if the estimated vehicle weight Wa is larger than the estimated vehicle weight Wb, if the determination in step S3 is affirmative, the process proceeds to step S4, where the estimated vehicle weight Wa is selected as the vehicle weight W. Is set.

  As described above, when one of the estimated vehicle weight Wa and the estimated vehicle weight Wb obtained by the two methods is selected and set as the vehicle weight W, the larger one of the estimated vehicle weights Wa and Wb is selected. Since the smaller estimated vehicle weight is selected as the vehicle weight W and the braking force of the vehicle is set, a relatively large braking force is set. Safety during braking can be ensured.

  When the vehicle weight W is set, the magnitude of the braking force (target braking force) applied to each wheel is set in consideration of the vehicle weight W and the traveling environment of the vehicle (block B30). In this case, the braking force (target braking force) is set to increase as the vehicle weight W (that is, the estimated vehicle weight Wa or the estimated vehicle weight Wb) increases.

  Here, the traveling environment of the vehicle considered when setting the braking force is, for example, the inclination angle of the traveling road surface, the friction coefficient of the traveling road surface, the air resistance that the vehicle receives during traveling, or the brake of the braking device 1 Each factor relating to the traveling environment or the traveling state of the vehicle, which can be a factor that varies the magnitude of the braking force during braking of the vehicle, such as the friction coefficient of the pad, is shown. As these factors, for example, the road surface inclination angle and the friction coefficient are detected from the calculation results based on the detection values of the longitudinal acceleration sensor 106 or the detection values of the wheel speed sensors 101, 102, 103, and 104 ( Block B31).

  When the target braking force applied to each wheel is set, in the hydraulic system of the braking device 1 for controlling the braking device 1 according to the target braking force and actually applying the braking force to each wheel. Brake fluid pressure control, that is, braking control by an electronically controlled brake system that electrically controls brake fluid pressure supplied to each wheel in accordance with a driver's braking operation is executed (block B40). When the above brake fluid pressure control is executed, the actual deceleration Gr is detected as the deceleration at that time (block B50).

  As described above, by executing the control by the control device of the present invention, the energy Em output from the motor M and the change amount ΔV of the vehicle speed V are detected, and the estimated vehicle weight Wa is based on the detected values. Is calculated. Further, the driving torque Tm of the motor M and the longitudinal acceleration α of the vehicle are detected, and the estimated vehicle weight Wb is calculated based on the detected values. When the temperature Hm of the motor M is outside a predetermined temperature range determined as a temperature range in which the motor M is stably operated, the estimated vehicle weight Wb is taken into account when setting the braking force of the vehicle. The vehicle weight W is selected so that the braking force applied to the wheels increases as the vehicle weight W increases. For example, in a state where the operation of the motor M is not stable, such as immediately after starting, the energy output by the motor M cannot be detected with high accuracy, and the estimation accuracy of the estimated vehicle weight Wa may decrease. In this case, the estimated vehicle weight Wb Is selected and the vehicle weight W is set, it is possible to ensure the estimation accuracy of the vehicle weight W and perform appropriate braking force control.

  When the temperature Hm of the motor M is within the predetermined temperature range, the estimated vehicle weight Wa and the estimated vehicle weight Wb are compared, and the larger one of them is selected as the vehicle weight W. Therefore, a larger braking force is set as compared with the case where the braking force is set based on the smaller vehicle weight, and the vehicle can be braked more reliably.

  Further, when the braking force (target braking force) is set, for example, a traveling environment such as a road surface inclination angle, a road surface friction coefficient, or air resistance is detected, and the traveling environment is taken into consideration and the braking force of the vehicle Ve is considered. Since (target braking force) is set, more appropriate braking force control can be performed.

  Here, the relationship between the above-described specific example and the present invention will be briefly described. The functional means of the block B21 described above corresponds to the energy detecting means of the present invention, and the functional means of the block B22 is the same as that of the present invention. It corresponds to vehicle speed change amount detection means, and the functional means of block B23 corresponds to the first vehicle weight calculation means of this invention. The functional means of the block B25 corresponds to the driving force detecting means of the present invention, and the functional means of the block B26 corresponds to the acceleration detecting means of the present invention. The functional means of the block B31 corresponds to the traveling environment detection means of the present invention, and the functional means of the blocks B20 and B30 correspond to the braking force setting means of the present invention.

It is a block diagram for demonstrating the example of control by the control apparatus of this invention. It is a flowchart for supplementing and explaining the control by the block diagram of FIG. It is a conceptual diagram which shows the hydraulic system regarding braking force control among the structures of the braking device used for the control apparatus of this invention. It is a block diagram which shows roughly the control system used for the control apparatus of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Braking device, 2 ... Master cylinder, 3, 4, 5, 6 ... Wheel cylinder, 21 ... Accumulator, 51 ... Master cylinder pressure sensor, 52 ... Accumulator pressure sensor, 53, 54, 55, 56 ... Wheel cylinder pressure sensor DESCRIPTION OF SYMBOLS 100 ... Electronic control device 101,102,103,104 ... Wheel speed sensor, 105 ... Brake pedal sensor (stroke sensor), 106 ... Longitudinal acceleration sensor, 107 ... Temperature sensor.

Claims (5)

In a vehicle braking control device for controlling a braking force applied to a wheel by controlling a brake fluid pressure in a wheel cylinder according to a driver's braking operation,
Energy detecting means for detecting energy output from the driving force source;
Vehicle speed change detecting means for detecting a change in vehicle speed;
First vehicle weight calculation means for calculating a vehicle weight based on the energy detected by the energy detection means and the change amount of the vehicle speed detected by the vehicle speed change detection means;
A braking control device for a vehicle, comprising: braking force setting means for setting the braking force to be larger as the vehicle weight calculated by the first vehicle weight calculating means is larger. Temperature detecting means for detecting the temperature of the driving force source;
Driving force detecting means for detecting the driving force of the driving force source;
Acceleration detecting means for detecting longitudinal acceleration of the vehicle;
A second vehicle weight calculating means for calculating a vehicle weight based on the driving force detected by the driving force detecting means and the longitudinal acceleration detected by the acceleration detecting means;
The braking force setting means uses the vehicle weight calculated by the second vehicle weight calculating means when the temperature of the driving force source detected by the temperature detecting means is outside a predetermined temperature range. The vehicle braking control apparatus according to claim 1, further comprising means for setting   The braking force setting means sets the braking force using a larger one of the vehicle weight calculated by the first vehicle weight calculating means and the vehicle weight calculated by the second vehicle weight calculating means. The vehicle braking control device according to claim 1, wherein the vehicle braking control device includes: The vehicle further comprises traveling environment detection means for detecting the traveling environment of the vehicle,
The vehicle braking according to any one of claims 1 to 3, wherein the braking force setting means includes means for setting the braking force based on the traveling environment detected by the traveling environment detection means. Control device.   5. The vehicle braking control apparatus according to claim 1, wherein the driving force source is a motor or a motor generator.

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