JP5620864B2 - Vehicle weight estimation device, vehicle weight estimation method, and vehicle rollover suppression device - Google Patents

Description

  The present invention relates to a vehicle weight estimation device and a vehicle weight estimation method. The present invention also relates to a vehicle rollover suppressing device that suppresses vehicle rollover.

  Conventionally, as an apparatus for estimating a vehicle weight, for example, an estimation apparatus described in Patent Document 1 has been proposed. In this estimation device, based on the vehicle body acceleration acquired before the change of the shift stage of the in-vehicle transmission and the drive torque at that time, and the vehicle body acceleration acquired after the change of the shift stage and the drive torque at that time, the vehicle A weight estimate is calculated. When an operation signal for the parking brake of the vehicle is input to the estimation device, it is determined that the vehicle weight may have changed, and the calculated estimated value of the vehicle weight is reset to an initial value. Thereafter, when the vehicle re-starts, the estimated value of the vehicle weight is calculated again in response to the shift of the transmission gear.

  In addition, in a vehicle with a power take-off device such as a construction truck or a concrete mixer truck, even when an operation signal from the power take-off device is input to the estimation device, the calculated estimated vehicle weight is the initial value. Reset to value. The “power take-off device” refers to a mechanism that extracts the power of a drive source (such as an engine) for driving a vehicle to drive the work machine.

  Note that the estimated value of the vehicle weight is used as a control parameter in various vehicle controls such as shift control, engine control, and braking control of an on-vehicle automatic transmission.

JP 2002-286535 A

  By the way, when the loading amount of the vehicle changes before and after the stop, the control parameter such as the estimated value of the vehicle weight used before the stop becomes unnecessary. For this reason, in the estimation device described in Patent Document 1, it is determined that the loading amount has changed when the stopping condition in which the operation signal from the parking brake or the operation signal from the power take-off device is input is satisfied. The estimated value is reset to the initial value. Then, after the vehicle starts, a control process for newly estimating the vehicle weight is performed. On the other hand, when the stop condition is not satisfied, the control parameters such as the estimated vehicle weight used before the stop are used as they are even after the vehicle starts.

  However, even if the stop condition is satisfied, the loading amount does not always change. Therefore, when such a determination method is combined with a method of calculating vehicle weight data for each predetermined period and statistically processing each vehicle weight data to obtain an estimated value of the vehicle weight, the load amount actually changes. If the stop condition is satisfied even if it is not, the process for obtaining the estimated value of the vehicle weight needs to be performed from the beginning. That is, the estimated value of the vehicle weight based on a plurality of vehicle weight data calculated every predetermined period after the start of the vehicle after the start of the vehicle even though the estimated value of the vehicle weight has already been determined by statistical processing or the like. The operation is performed from the beginning.

  In such statistical processing, when the number of vehicle weight data is small, the accuracy of the estimated value of the vehicle weight is lower than when the number is large. Therefore, until the accuracy of the estimated value of the vehicle weight becomes high, there is a possibility that an effective effect cannot be obtained by the vehicle control using the estimated value of the vehicle weight.

  The present invention has been made in view of such circumstances. The purpose of the vehicle weight is to improve the estimation accuracy of the estimated value of the vehicle weight after the start of the vehicle when determining the estimated value of the vehicle weight based on the vehicle weight data periodically calculated when the vehicle is traveling. The present invention provides an estimation device, a vehicle weight estimation method, and a vehicle rollover suppression device.

  In order to achieve the above object, the vehicle weight estimation apparatus of the present invention is calculated by vehicle weight data calculation means (30, S20) for calculating vehicle weight data (M) for each preset period. Based on vehicle weight data (M) equal to or greater than a predetermined number (Y), first estimated value acquisition means (30, S23) for acquiring a first estimated value (Mave) of vehicle weight, and for determining that the vehicle has stopped. A stop determination means (30, S16, S17, S18) for determining whether or not the stop condition is satisfied, and when it is determined that the stop condition is satisfied, an estimated value (MS) of the vehicle weight is an initial value. Reset means (30, S27) for resetting to (MS_Re) and the predetermined number calculated by the vehicle weight data calculating means (30, S20) after the vehicle starts when the vehicle starts after the stop condition is satisfied Less than (Y) Based on the vehicle weight data (M), the second estimated value acquisition means (30, S29) for acquiring the second estimated value (Mn) of the vehicle weight, and when the vehicle starts after the stop condition is satisfied, The second estimated value (Mn) of the vehicle weight acquired by the estimated value acquiring means (30, S29) and the vehicle acquired by the first estimated value acquiring means (30, S23) before the stop condition is satisfied. When the difference (ΔM) from the first estimated value (Mave, Ma) of the weight is less than a determination value (Mth) set as a determination criterion as to whether or not the vehicle weight has changed, the vehicle weight is estimated. The gist is provided with estimated value determining means (30, S33) for returning the value (MS) from the initial value (MS_Re) to the first estimated value (Mave, Ma) of the vehicle weight.

  According to the above configuration, when the vehicle is traveling, the first estimated value of the vehicle weight is acquired based on a plurality of vehicle weight data that is equal to or greater than a predetermined number calculated for each preset period. Then, the first estimated value of the vehicle weight is determined as the estimated value of the vehicle weight. Further, when the stop condition is satisfied, the estimated value of the vehicle weight is determined as an initial value. Thereafter, when the vehicle starts, the second estimated value of the vehicle weight is acquired based on the vehicle weight data less than the predetermined number acquired after the start. If the difference between the second estimated value and the first estimated value of the vehicle weight acquired before the stop condition is satisfied is less than the determination value, the estimated value of the vehicle weight is calculated from the initial value before the stop condition is satisfied. (That is, the first estimated value of the vehicle weight).

  In other words, in the present invention, when it is determined that the loading amount of the vehicle has not changed before and after the stop condition is satisfied, the estimated value of the vehicle weight is the first estimate of the vehicle weight acquired before the stop condition is satisfied. Returns to value promptly. Therefore, although the first estimated value of the vehicle weight before the stop condition is satisfied can be used, the vehicle weight is estimated until the number of vehicle weight data calculated after the start exceeds a predetermined number. It is avoided that the first estimated value is acquired based on the vehicle weight data of a predetermined number or more newly acquired with the value as an initial value. That is, the estimated value of the vehicle weight after the start of the vehicle is quickly determined to be a highly accurate value as compared with the case where the control process for obtaining the first estimated value is started again after the start of the vehicle. Therefore, when the estimated value of the vehicle weight is determined based on the vehicle weight data periodically calculated when the vehicle is traveling, the estimation accuracy of the estimated value of the vehicle weight after the start of the vehicle can be improved.

Further, by using a highly accurate estimated value of the vehicle weight as a control parameter for vehicle control, an effective effect can be obtained by the vehicle control.
In the vehicle weight estimation apparatus according to the present invention, the estimated value determining means (30, S27, S33) is configured such that the vehicle weight data after the vehicle starts when the difference (ΔM) is equal to or greater than the determination value (Mth). When the number of data (X) of the vehicle weight data (M) calculated by the calculation means (30, S20) is less than the predetermined number (Y), the estimated value (MS) of the vehicle weight is set to the initial value (MS_Re). When the number of data (X) of the vehicle weight data (M) calculated after starting the vehicle is equal to or greater than the predetermined number (Y), the estimated value (MS) of the vehicle weight is set to the first estimated value. It is preferable to use the first estimated value (Mave) of the vehicle weight acquired by the acquiring means (30, S23).

  According to the above configuration, when the difference is greater than or equal to the determination value, it is determined that the loading amount of the vehicle has changed before and after the stop condition is satisfied. As a result, the estimated value of the vehicle weight is set to the initial value until the number of vehicle weight data calculated after the stop condition is satisfied becomes equal to or greater than the predetermined number. Thereafter, when the number of data of vehicle weight data calculated for each period after the stop condition is satisfied becomes equal to or greater than a predetermined number, a first estimated value of vehicle weight is newly acquired based on each vehicle weight data. Then, the estimated value of the vehicle weight is changed to the newly acquired first estimated value. That is, the initial value can be used as the estimated value of the vehicle weight until the highly accurate first estimated value of the vehicle weight is acquired.

  In the vehicle weight estimation apparatus according to the present invention, the determination value (Mth) is smaller when the estimated value (MS, Ma) of the vehicle weight before being reset by the reset means (30, S27) is large. It is preferable to further include determination value setting means (30, S31) for setting a larger value.

  When the vehicle weight is heavy, it is considered that the error amount of the second estimated value of the vehicle weight with respect to the actual weight of the vehicle becomes larger than when the vehicle weight is light. Therefore, in the present invention, the determination value is set based on the estimated value of the vehicle weight before being reset to the initial value. Therefore, it is possible to improve the accuracy of determining whether or not the vehicle weight has changed while the vehicle is stopped, regardless of the actual weight of the vehicle.

  In the vehicle weight estimation apparatus of the present invention, the stopping condition is that a braking force is applied to the wheel (10) by the parking brake (25) of the vehicle, and an elapsed time (Ts) after the vehicle stops. It is preferable to include at least one of those that are equal to or longer than a preset stoppage determination time (Tsth).

  According to the above configuration, when the parking brake of the vehicle is operated and when the vehicle stops for a stop determination time or more, it is determined that the vehicle weight may have changed during the stop. Then, the estimated value of the vehicle weight is reset to the initial value.

The present invention relates to a vehicle rollover suppression device that performs rollover suppression control that suppresses vehicle rollover, and calculates the vehicle weight estimation device (14, 30) and the lateral acceleration (Gy) of the vehicle. an acceleration calculating means (30, S41), wherein the threshold (Gyth) for specifying a start timing of the rollover prevention control, the vehicle weight estimation apparatus computed vehicle weight estimates by (14, 30) (MS ) Is large, the threshold value setting means (30, S42) is set to a smaller value than the small value, and the lateral acceleration (Gy) acquired by the lateral acceleration calculation means (30, S41) is the threshold value. The gist is provided with control means (30, S44) for starting the rollover suppression control when it is equal to or greater than the threshold value (Gyth) set by the setting means (30, S42).

  As the weight is heavier, the center of gravity of the vehicle moves upward, so the possibility of the vehicle rolling over increases. Therefore, in the present invention, the threshold value for specifying the start timing of the rollover suppression control is set based on the determined estimated value of the vehicle weight. Therefore, in a heavy vehicle, the rollover suppression control is started at an early timing, so that the vehicle can be prevented from rollover. On the other hand, in a light vehicle, it is suppressed that the rollover suppression control is started at a timing when the possibility of rollover is low. That is, inadvertent execution of the rollover suppression control can be suppressed.

  The vehicle weight estimation method of the present invention includes a vehicle weight data calculation step (S20) for calculating vehicle weight data (M) for each preset period, and vehicle weight data (Y) greater than or equal to the calculated number (Y). M), a first estimated value acquisition step (S23) for acquiring a first estimated value (Mave) of the vehicle weight, and a stop for determining whether or not a stop condition for determining that the vehicle has stopped is satisfied. A determination step (S16, S17, S18), a reset step (S27) for resetting an estimated value (MS) of the vehicle weight to an initial value (MS_Re) when it is determined that the stop condition is satisfied, and the stop condition Vehicle weight based on vehicle weight data (M) less than the predetermined number (Y) calculated in the vehicle weight data calculation step (S20) after the vehicle starts. The second estimated value acquisition step (S29) for acquiring the second estimated value (Mn) and the vehicle weight acquired in the second estimated value acquisition step (S29) at the start of the vehicle after the stop condition is satisfied. 2 The difference (ΔM) between the estimated value (Mn) and the first estimated value (Mave, Ma) of the vehicle weight acquired in the first estimated value acquiring step (23) before the stop condition is satisfied is the vehicle weight. Is less than a determination value (Mth) set as a determination criterion as to whether or not the vehicle has changed, the vehicle weight estimated value (MS) is changed from the initial value (MS_Re) to the first estimated value of the vehicle weight. And an estimated value determining step (S34) for returning to (Mave, Ma).

  According to the said structure, the effect | action and effect equivalent to the said vehicle weight estimation apparatus can be acquired.

1 is a block diagram showing an embodiment of a vehicle including a vehicle weight estimation device according to the present invention. The flowchart explaining the vehicle weight estimation processing routine (first half part). The flowchart explaining the vehicle weight estimation processing routine (second half part). The flowchart explaining a rollover suppression process routine. The timing chart which shows the change of the estimated value of vehicle weight when the actual weight of a vehicle does not change while a vehicle stops. The timing chart which shows the change of the estimated value of vehicle weight when the actual weight of a vehicle changes while the vehicle stops.

  Hereinafter, an embodiment embodying the present invention will be described with reference to FIGS. In the following description of the present specification, the traveling direction (forward direction) of the vehicle is assumed to be the front (front of the vehicle).

  As shown in FIG. 1, the vehicle is provided with a power transmission mechanism 12 for transmitting a driving force generated by the engine 11 to a plurality of (for example, four) wheels 10. The power transmission mechanism 12 includes a transmission 120 disposed on the engine 11 side in the power transmission path, a differential 121 disposed on the wheel 10 side in the power transmission path, and the like. The transmission 120 of the present embodiment is set to a gear position according to an operation mode of a shift operation unit (not shown) by a vehicle driver.

  Further, the vehicle is provided with an engine ECU 14 (also referred to as an “engine electronic control device”) that controls the engine 11 based on the operation mode of the accelerator pedal 13 by the driver. The engine ECU 14 includes an accelerator opening sensor SE1 for detecting an operation amount of the accelerator pedal 13, that is, an accelerator opening, and a rotation speed detection sensor SE2 for detecting the rotation speed of the output shaft 122 of the transmission 120. And are electrically connected. Then, the engine ECU 14 calculates the accelerator opening based on the detection signal from the accelerator opening sensor SE1, and controls the engine 11 based on the calculated accelerator opening. Further, the engine ECU 14 calculates the rotational speed of the output shaft 122 of the transmission 120 based on the detection signal from the rotational speed detection sensor SE2, and is applied to the vehicle based on the drive of the engine 11 based on the calculated rotational speed. Calculate drive torque.

  The vehicle is also provided with a braking device 20 for applying a braking force to each wheel 10. The braking device 20 includes a hydraulic pressure generating device 21 having a booster, a master cylinder and a reservoir (not shown), and a brake actuator 22. When the driver operates the brake pedal 23, a hydraulic pressure corresponding to the operation amount of the brake pedal 23 is generated in the master cylinder of the hydraulic pressure generator 21. Then, the amount of brake fluid corresponding to the fluid pressure in the master cylinder flows into a wheel cylinder 24 provided for each wheel 10 via a fluid pressure circuit (not shown) of the brake actuator 22. As a result, a braking force corresponding to the hydraulic pressure in the corresponding wheel cylinder 24 is applied to each wheel 10.

  The braking device 20 of the present embodiment has a function of adjusting the magnitude of the braking force for each wheel 10 when the driver operates the brake pedal 23, and a function of applying a braking force to the wheel 10 when the brake pedal 23 is not operated. have. In order to realize such a function, the brake actuator 22 includes a differential pressure valve for generating a differential pressure between the master cylinder and the wheel cylinder 24, a pump for supplying brake fluid into the wheel cylinder 24, A pressure reducing valve that operates when the pressure in the wheel cylinder 24 is reduced, a holding valve that operates when pressure increase in the wheel cylinder 24 is regulated, and the like are provided.

  Further, the vehicle is provided with a parking brake 25 that applies a braking force to some of the wheels 10 when a parking operation unit (not shown) is operated by the driver. When the parking brake 25 is operated so as to apply a braking force to some of the wheels 10, a brake ECU 30 (an “brake electronic control device”) is used as an example of a vehicle weight estimation device. Output).

  The brake ECU 30 calculates an estimated value of the vehicle weight, and uses the estimated value of the vehicle weight to perform rollover suppression control for suppressing rollover when the vehicle is turning. That is, in the present embodiment, the brake ECU 30 also functions as a vehicle rollover suppressing device. In the present embodiment, the vehicle weight is a weight including at least the weight of the vehicle itself (also referred to as “body weight”) and the weight of the load loaded on the vehicle and the weight based on the passenger on the vehicle. is there. Further, the rollover suppression control is a control for operating the brake actuator 22 to individually adjust the braking force for each wheel 10 in order to reduce the lateral acceleration of the vehicle.

  The brake ECU 30 is electrically connected to a brake switch SW1 for detecting whether or not the driver has operated the brake pedal 23 and a wheel speed sensor SE3 for detecting the wheel speed of the wheel 10. . The brake ECU 30 is electrically connected to a longitudinal acceleration sensor SE4 for detecting longitudinal acceleration (vehicle acceleration) of the vehicle and a lateral acceleration sensor SE5 for detecting lateral acceleration of the vehicle. Has been. Furthermore, the brake ECU 30 can communicate with the engine ECU 14. For example, the brake ECU 30 receives information (for example, drive torque) necessary for estimating the vehicle weight from the engine ECU 14 via the bus 40.

  The longitudinal acceleration sensor SE4 outputs a signal that becomes a positive value when the center of gravity of the vehicle moves backward, whereas it becomes a negative value when the center of gravity of the vehicle moves forward. Is output. Therefore, when the vehicle is stopped on an uphill road, the longitudinal acceleration calculated based on the detection signal from the longitudinal acceleration sensor SE4 is a positive value. When the vehicle is stopped on a downhill road, the longitudinal acceleration calculated based on the detection signal from the longitudinal acceleration sensor SE4 is a negative value.

  The brake ECU 30 includes a CPU 31, a ROM 32, a RAM 33, an EEPROM 34 as an example of a nonvolatile memory, and the like. The ROM 32 stores in advance a control program executed by the CPU 31 and various maps when estimating the vehicle weight or performing various braking controls. The RAM 33 stores various types of information (wheel speed and the like) that can be appropriately rewritten while an ignition switch (not shown) of the vehicle is on. As will be described in detail later, the EEPROM 34 is provided with a storage area 341 in which vehicle weight data calculated based on the longitudinal acceleration of the vehicle and the driving torque received from the engine ECU 14 is stored. Therefore, in the present embodiment, the EEPROM 34 functions as a storage unit.

  When the longitudinal acceleration of the vehicle is less than a detection limit value (for example, 0.05 G), the accuracy of the longitudinal acceleration is extremely reduced due to the limit due to the performance of the longitudinal acceleration sensor SE4, or the longitudinal acceleration is reduced. Cannot calculate. Therefore, precisely, the storage area 341 stores vehicle weight data calculated when the longitudinal acceleration Gx is equal to or greater than the detection limit value.

  Note that each detection signal from the rotational speed detection sensor SE2 and the longitudinal acceleration sensor SE4 includes a substantially constant amount of noise components regardless of the signal magnitude. Therefore, in the present embodiment, the vehicle weight data M is calculated for each predetermined period set in advance. Then, a normal estimated value of vehicle weight (first estimated value of vehicle weight) is calculated using a predetermined number of vehicle weight data M set in advance. The predetermined number is an integer greater than or equal to “1”, which is considered that a highly accurate estimated value of the vehicle weight can be obtained by performing statistical processing with the number of data. In this embodiment, the predetermined number is set to “15”, for example.

  Next, various control processing routines executed by the brake ECU 30 of the present embodiment will be described with reference to the flowcharts shown in FIGS. 2, 3, and 4 and the timing charts shown in FIGS. 5 and 6. 2 and 3 are flowcharts illustrating a weight estimation processing routine executed when calculating an estimated value of the vehicle weight, and FIG. 4 illustrates a rollover suppression processing routine for suppressing the vehicle rollover. The flowchart which performs is shown. FIG. 5 shows a timing chart for explaining how the estimated value of the vehicle weight changes when the actual weight of the vehicle does not change while the vehicle is stopped, and FIG. 6 shows a case where the actual weight of the vehicle changes while the vehicle is stopped. 2 is a timing chart for explaining a change mode of an estimated value of the vehicle weight in FIG.

First, the weight estimation processing routine will be described.
Now, the weight estimation processing routine is executed every predetermined time (for example, every 6 milliseconds) set in advance. In the weight estimation processing routine, the brake ECU 30 calculates the wheel speed VW of each wheel 10 based on the detection signal from the wheel speed sensor SE3 for each wheel (step S10). Subsequently, the brake ECU 30 calculates the vehicle body speed VS of the vehicle based on the wheel speed VW of at least one of the calculated wheel speeds VW (step S11), and per unit time of the vehicle speed VS. A vehicle body speed differential value DVS, which is a change amount of the vehicle, is calculated (step S12).

  Then, the brake ECU 30 calculates the vehicle longitudinal acceleration (vehicle acceleration) Gx based on the detection signal from the longitudinal acceleration sensor SE4 (step S13). Therefore, in the present embodiment, the brake ECU 30 also functions as acceleration calculation means. Subsequently, the brake ECU 30 subtracts the longitudinal acceleration Gx calculated in step S13 from the vehicle body speed differential value DVS calculated in step S12, and acquires the road surface gradient θ based on the calculation result (step S14). A difference is generated between the vehicle body speed differential value DVS and the longitudinal acceleration Gx according to the gradient of the road surface on which the vehicle travels. The road surface gradient θ is obtained using this difference.

  Then, the brake ECU 30 acquires the drive torque F from the engine ECU 14 (step S15). Subsequently, the brake ECU 30 determines whether or not the parking brake 25 is operating (step S16). In step S <b> 16, it is determined whether or not braking force is applied to some of the wheels 10 by the parking brake 25. If the parking brake 25 is in operation (step S16: YES), the brake ECU 30 determines that a stop condition for determining that the vehicle has stopped is satisfied, and the process proceeds to step S25 described later. On the other hand, when the parking brake 25 is not in operation (step S16: NO), the brake ECU 30 determines that the vehicle body speed VS calculated in step S11 is less than a preset stoppage determination speed VSth (for example, 3 km / h). Whether or not (step S17).

  When the vehicle body speed VS is equal to or higher than the stop determination speed VSth (step S17: NO), the brake ECU 30 determines that the stop condition is not satisfied, and the process proceeds to step S19 described later. On the other hand, when the vehicle body speed VS is less than the stoppage determination speed VSth (step S17: YES), the brake ECU 30 determines that the elapsed time Ts from when the vehicle body speed VS is less than the stoppage determination speed VSth is set in advance. It is determined whether it is time Tsth (for example, 30 seconds) or more (step S18). This stop determination time Tsth is set based on, for example, the minimum time required for carrying the baggage into and out of the vehicle. The elapsed time Ts is reset to “0 (zero)” seconds when the vehicle body speed VS becomes equal to or higher than the stoppage determination speed VSth.

  When the elapsed time Ts is equal to or longer than the stop determination time Tsth (step S18: YES), the brake ECU 30 determines that the stop condition is satisfied, and the process proceeds to step S25 described later. On the other hand, when the elapsed time Ts is less than the stop determination time Tsth, the brake ECU 30 determines that the stop condition is not satisfied, and the process proceeds to the next step S19. Therefore, in the present embodiment, the brake ECU 30 also functions as a stop determination unit. In addition, a stop determination step is configured by steps S16, S17, and S18.

  In step S19, the brake ECU 30 determines whether or not the brake switch SW1 is off. When the brake switch SW1 is on (step S19: NO), the brake ECU 30 temporarily ends the weight estimation processing routine because the braking force is applied to each wheel 10 by the operation of the brake pedal 23 by the driver. . On the other hand, when the brake switch SW1 is off (step S19: YES), the brake ECU 30 performs a calculation process of the vehicle weight data M because the braking force is not applied to the wheel 10 (step S20). For example, the brake ECU 30 calculates the vehicle weight data M using the following relational expressions (Expression 1) to (Expression 5). Therefore, in the present embodiment, the brake ECU 30 also functions as vehicle weight data calculation means for calculating the vehicle weight data M at predetermined intervals set in advance based on the longitudinal acceleration Gx. Step S20 corresponds to a vehicle weight data calculation step. When the longitudinal acceleration Gx is less than the detection limit value, the vehicle weight data M is not calculated.

ただし、Ｆ…駆動トルク、Ｆ１…車両の慣性力、Ｆ２…路面勾配に基づく勾配抵抗、Ｆ３…路面と車輪との間の摩擦抵抗（走行抵抗）、Ｆ４…車両に対する空気抵抗、ｇ…重力加速度、μ…摩擦係数、Ａ…空気抵抗を取得するために設定された所定値
そして、ブレーキ用ＥＣＵ３０は、仮リセットフラグＦＬＧ１がオンであるか否かを判定する（ステップＳ２１）。この仮リセットフラグＦＬＧ１は、上記停車条件が成立したと判定された場合にオンにセットされるフラグである。仮リセットフラグＦＬＧ１がオンである場合（ステップＳ２１：ＹＥＳ）、ブレーキ用ＥＣＵ３０は、その処理を後述するステップＳ２８に移行する。一方、仮リセットフラグＦＬＧ１がオフである場合（ステップＳ２１：ＮＯ）、ブレーキ用ＥＣＵ３０は、ステップＳ２０で演算した今回の車両重量データＭを、上記記憶領域３４１に記憶させる。そして、ブレーキ用ＥＣＵ３０は、車両の発進後に所定周期毎に演算された車両重量データＭのデータ数Ｘが上記既定数Ｙ以上であるか否かを判定する（ステップＳ２２）。データ数Ｘが既定数Ｙ未満である場合（ステップＳ２２：ＮＯ）、ブレーキ用ＥＣＵ３０は、正確性の高い車両重量の推定値を取得できないと判断し、重量推定処理ルーチンを一旦終了する。

F: Driving torque, F1: Inertial force of the vehicle, F2: Gradient resistance based on the road surface gradient, F3: Friction resistance (running resistance) between the road surface and wheels, F4: Air resistance against the vehicle, g: Gravity acceleration , Μ ... friction coefficient, A ... predetermined value set to acquire air resistance Then, the brake ECU 30 determines whether or not the temporary reset flag FLG1 is on (step S21). The temporary reset flag FLG1 is a flag that is turned on when it is determined that the stop condition is satisfied. If the temporary reset flag FLG1 is on (step S21: YES), the brake ECU 30 proceeds to step S28 to be described later. On the other hand, when the temporary reset flag FLG1 is off (step S21: NO), the brake ECU 30 stores the current vehicle weight data M calculated in step S20 in the storage area 341. Then, the brake ECU 30 determines whether or not the number X of vehicle weight data M calculated every predetermined period after the vehicle starts is equal to or greater than the predetermined number Y (step S22). When the number of data X is less than the predetermined number Y (step S22: NO), the brake ECU 30 determines that a highly accurate estimated value of the vehicle weight cannot be obtained, and once ends the weight estimation processing routine.

  On the other hand, when the data number X is equal to or greater than the predetermined number Y (step S22: YES), the brake ECU 30 performs a statistical process using all the vehicle weight data M stored in the storage area 341 after the vehicle starts. A normal estimated value of weight (first estimated value of vehicle weight) Mave is acquired (step S23). Specifically, in step S23, an average process for calculating an average value of the plurality of vehicle weight data M is performed, and the average value is set as a normal estimated value Mave of the vehicle weight.

  Subsequently, the brake ECU 30 sets the vehicle weight normal estimated value Mave acquired in step S23 as the vehicle weight estimated value MS (step S24), and once ends the weight estimation processing routine. Therefore, in the present embodiment, the brake ECU 30 also functions as first estimated value acquisition means for acquiring the normal estimated value Mave of the vehicle weight based on the calculated vehicle weight data M equal to or greater than the predetermined number Y. Step S23 corresponds to a first estimated value acquisition step.

  That is, as shown in the timing chart of FIG. 5, when the vehicle in a stopped state starts, the number of data X of the vehicle weight data M increases until the first timing t11 when the brake switch SW1 is turned on. The normal estimated value Mave (= estimated value MS) of the vehicle approaches the actual weight MR of the vehicle. When the first timing t11 when the driver operates the brake pedal 23 has elapsed, the vehicle weight data M is not calculated. In this case, the estimated value MS of the vehicle weight is maintained at the normal estimated value Mave calculated immediately before the first timing t11.

  Returning to the flowcharts of FIG. 2 and FIG. 3, when the determination result in steps S17 and S18 is affirmative (YES), the brake ECU 30 executes the process of step S25. In step S25, the brake ECU 30 determines that the vehicle stop condition is satisfied, and therefore sets the temporary reset flag FLG1 to ON. Subsequently, the brake ECU 30 sets the pre-reset estimated value Ma as the current vehicle weight estimated value MS, and stores the pre-reset estimated value Ma in a predetermined storage area of the EEPROM 34 (step S26). That is, the estimated value Ma before reset corresponds to the normal estimated value Mave of the vehicle weight before the estimated value MS of the vehicle weight is reset. Since the vehicle weight may change while the vehicle is stopped, the brake ECU 30 sets the estimated value MS of the vehicle weight as the initial value MS_Re (step S27). The initial value MS_Re is a value corresponding to the vehicle weight when the vehicle load is maximized or a value larger than the vehicle weight. Therefore, in the present embodiment, the brake ECU 30 also functions as a reset unit. Step S27 corresponds to a reset step. Thereafter, the brake ECU 30 once ends the weight estimation processing routine.

  That is, as shown in the timing chart of FIG. 5, at the second timing t12 when the vehicle stops and the temporary reset flag FLG1 is set to ON, the estimated value MS of the vehicle weight is reset to the initial value MS_Re. The estimated value MS of the vehicle weight is maintained at the initial value MS_Re until the third timing t13 when the vehicle restarts.

  Returning to the flowcharts of FIG. 2 and FIG. 3, when the determination result of step S21 is affirmative (YES), the brake ECU 30 determines that the vehicle in the stopped state has restarted, and performs the process of step S28. In this step S28, the brake ECU 30 determines whether or not the data number X of the vehicle weight data M calculated after the vehicle starts is equal to or greater than a predetermined number Z set in advance. The predetermined number Z is set in advance to a value (for example, 3) smaller than the predetermined number Y when the normal estimated value Mave of the vehicle weight is acquired.

  When the number of data X is less than the predetermined number Z (step S28: NO), the brake ECU 30 once ends the weight estimation processing routine. On the other hand, when the number of data X is equal to or greater than the predetermined number Z (step S28: YES), the brake ECU 30 calculates an average value of the predetermined number Z of vehicle weight data M acquired after the vehicle restarts, and calculates the average The value is set as a provisional estimated value (second estimated value of vehicle weight) Mn (step S29). Therefore, in the present embodiment, the brake ECU 30 also functions as a second estimated value acquisition unit. Step S29 corresponds to a second estimated value acquisition step.

  Subsequently, the brake ECU 30 acquires a difference ΔM between the provisional estimated value Mn calculated in step S29 and the estimated value Ma before reset set in step S26 (step S30). Then, the brake ECU 30 multiplies the pre-reset estimated value Ma by a preset gain value TH, and sets the calculation result as a determination value Mth (step S31). The gain value TH is preferably “0.5” or less, and is set to “0.3”, for example. Therefore, in the present embodiment, the brake ECU 30 determines that the determination value Mth for determining whether or not the vehicle weight has changed is set to a larger value when the pre-reset estimated value Ma is large than when it is small. It also functions as a value setting means.

  Subsequently, the brake ECU 30 determines whether or not the absolute value of the difference ΔM calculated in step S30 is less than the determination value Mth calculated in step S31 (step S32). When the absolute value of the difference ΔM is less than the determination value Mth (step S32: YES), the brake ECU 30 determines that the vehicle weight has not changed while the vehicle is stopped, and before resetting to the estimated value MS of the vehicle weight. Estimated value Ma is set (step S33). That is, the brake ECU 30 returns the estimated value MS of the vehicle weight to a value (= Ma) before the estimated value MS is reset to the initial value MS_Re. Therefore, in the present embodiment, when the difference ΔM is less than the determination value Mth, the brake ECU 30 determines the vehicle weight estimated value MS from the initial value MS_Re before the stop condition is satisfied. It also functions as an estimated value determining means for returning to the normal estimated value Mave (= estimated value Ma before reset). Step S33 corresponds to an estimated value determination step. Thereafter, the brake ECU 30 sets the temporary reset flag FLG1 to OFF (step S34), and once ends the weight estimation processing routine.

  On the other hand, if the absolute value of the difference ΔM is greater than or equal to the determination value Mth (step S32: NO), the brake ECU 30 determines that the vehicle weight has changed and initializes the storage area 341 (step S35). When the process of step S35 is performed, the brake ECU 30 considers that the storage number of the vehicle weight data M in the storage area 341 is “0 (zero)”. Thereafter, the brake ECU 30 sets the temporary reset flag FLG1 to OFF (step S34), and once ends the weight estimation processing routine.

  That is, as shown in the timing chart of FIG. 5, when the brake switch SW1 is turned off, the vehicle restarts (third timing t13). When the longitudinal acceleration Gx is equal to or greater than the detection limit value, the vehicle weight data M is calculated every predetermined period. Then, when the predetermined number Z of vehicle weight data M used for acquisition of the provisional estimated value Mn is acquired, the provisional estimated value Mn is calculated (fourth timing t14). When the difference ΔM between the provisional estimated value Mn and the estimated value Ma before reset is less than the determination value Mth, it is determined that the actual weight MR of the vehicle has not changed while the vehicle is stopped. Then, the estimated value MS of the vehicle weight is returned from the initial value MS_Re to the estimated value Ma before reset. Therefore, even immediately after the vehicle restarts, there is almost no difference between the estimated value MS of the vehicle weight and the actual weight MR.

  On the other hand, as shown in the timing chart of FIG. 6, when the actual weight MR of the vehicle changes at the first timing t21 while the vehicle is stopped, the acceleration in the longitudinal direction is performed after the second timing t22 when the vehicle restarts. When Gx becomes equal to or greater than the detection limit value, the vehicle weight data M is calculated every predetermined period. Then, the provisional estimated value Mn is calculated at the third timing t23 when the predetermined number Z of vehicle weight data M is acquired. The provisional estimated value Mn is a value corresponding to the actual weight MR, although the accuracy is low. Therefore, the difference ΔM between the provisional estimated value Mn and the pre-reset estimated value Ma is equal to or greater than the determination value Mth.

  Then, the estimated value MS of the vehicle weight is held at the initial value MS_Re. Thereafter, when the data number X of the vehicle weight data M calculated after the start of the vehicle is equal to or greater than the predetermined number Y, an average process for averaging the plurality of vehicle weight data M is performed, whereby the normal estimated value Mave of the vehicle weight is obtained. Obtained (fourth timing t24). Then, the estimated value MS of the vehicle weight becomes the newly acquired normal estimated value Mave. Thereafter, by performing the averaging process for each predetermined cycle, the estimated value MS of the vehicle weight calculated based on the plurality of vehicle weight data M approaches the actual weight MR.

Next, the rollover suppression processing routine will be described with reference to the flowchart of FIG.
Now, the rollover suppression processing routine is executed every predetermined time (for example, every 6 milliseconds) set in advance. In the rollover suppression processing routine, the brake ECU 30 determines whether the brake switch SW1 is off (step S40). When the brake switch SW1 is on (step S40: NO), the brake ECU 30 once ends the rollover suppression processing routine because the driver is operating the brake pedal 23. On the other hand, when the brake switch SW1 is off (step S40: YES), the brake ECU 30 calculates the lateral acceleration Gy of the vehicle based on the detection signal from the lateral acceleration sensor SE5 (step S41). Therefore, in this embodiment, it functions also as a lateral acceleration calculation means.

  Subsequently, the brake ECU 30 sets the threshold value Gyth for specifying the start timing of the rollover suppression control to a smaller value when the estimated vehicle weight value MS is larger than when it is smaller (step S42). For example, the brake ECU 30 sets the threshold Gyth to the first value when the estimated value MS of the vehicle weight is equal to or greater than a preset weight threshold, and the estimated value MS of the vehicle weight is less than the weight threshold. , The threshold value Gyth is set to a second value larger than the first value. Therefore, in the present embodiment, the brake ECU 30 also functions as a threshold setting unit.

  Then, the brake ECU 30 determines whether or not the lateral acceleration Gy calculated in step S41 is equal to or greater than the threshold value Gyth set in step S42 (step S43). When the lateral acceleration Gy is less than the threshold value Gyth (step S43: NO), the brake ECU 30 determines that the possibility of the vehicle rollover is low, and temporarily ends the rollover suppression processing routine. On the other hand, if the lateral acceleration Gy is equal to or greater than the threshold value Gyth (step S43: YES), the brake ECU 30 determines that the vehicle may roll over and performs rollover suppression control (step S44), and rollover suppression processing is performed. The routine is temporarily terminated. Therefore, in the present embodiment, the brake ECU 30 also functions as a control unit.

  The threshold value Gyth is set to a value based on the estimated value MS of the vehicle weight. Moreover, by executing the vehicle weight estimation processing routine, the estimated value MS of the vehicle weight is set to a value very close to the actual weight MR of the vehicle. Therefore, it is possible to suppress the start of the rollover suppression control from being delayed or the rollover suppression control from being started unnecessarily. That is, when rollover suppression control is required, rollover suppression control is started at an appropriate timing.

Therefore, in this embodiment, the following effects can be obtained.
(1) When it is determined that the stop condition is satisfied, the initial value MS_Re is set as the estimated value MS of the vehicle weight. Thereafter, when the vehicle starts, a temporary estimated value Mn is acquired based on a predetermined number Z of vehicle weight data M calculated after the vehicle starts. If the vehicle weight has not changed while the vehicle is stopped, the provisional estimated value Mn should be approximately the same as the pre-reset estimated value Ma. Therefore, when the temporary estimated value Mn is acquired, a difference ΔM between the temporary estimated value Mn and the pre-reset estimated value Ma is calculated. When the absolute value of the difference ΔM is less than the determination value Mth, it is determined that the vehicle weight has not changed while the vehicle is stopped, and the estimated value MS of the vehicle weight is not reset to the initial value. The value is returned to the pre-reset estimated value Ma. Therefore, the estimation accuracy of the estimated value MS of the vehicle after the start of the vehicle is improved as compared with the case where the estimated value MS of the vehicle is recalculated after the start of the vehicle regardless of whether or not the vehicle weight changes while the vehicle is stopped. Can be made.

  (2) When the vehicle weight is heavy, it is considered that the error amount of the provisional estimated value Mn with respect to the actual weight MR of the vehicle becomes larger than when the vehicle weight is light. Therefore, in the present embodiment, the determination value Mth is set to a larger value as the pre-reset estimated value Ma is larger. Therefore, regardless of the actual weight MR of the vehicle, it is possible to improve the determination accuracy of whether or not the vehicle weight has changed while the vehicle is stopped.

  (3) The normal estimated value Mave of the vehicle weight is calculated based on a plurality of vehicle weight data M estimated every predetermined period. In this case, it is preferable that the number of samples of the vehicle weight data M is larger in order to obtain a highly accurate normal estimated value Mave of the vehicle weight after the vehicle starts. That is, it takes a lot of time to obtain a highly accurate estimated value MS of the vehicle weight after the vehicle starts. Therefore, in this embodiment, when the vehicle weight has not changed while the vehicle is stopped, the estimated value MS of the vehicle weight is returned to the estimated value Ma before reset. Therefore, after the vehicle starts, the estimated value MS of the vehicle weight can be quickly set to a value close to the actual weight MR of the vehicle.

  (4) When the difference ΔM is greater than or equal to the determination value Mth, it is determined that the vehicle weight has changed while the vehicle is stopped. In this case, the estimated value MS of the vehicle weight is set to the initial value MS_Re until the data number X of the vehicle weight data M calculated after the vehicle starts is equal to or greater than the predetermined number Y. When the normal estimated value Mave is acquired based on the predetermined number Y of vehicle weight data M calculated after the vehicle starts, the vehicle weight estimated value MS is set to the newly acquired normal estimated value Mave. Therefore, the initial value MS_Re can be used as the estimated value MS of the vehicle weight until a highly accurate normal estimated value Mave of the vehicle weight is acquired.

  (5) In the present embodiment, even when the parking brake 25 is not operated, if the elapsed time Ts after the vehicle stops is equal to or longer than the stop determination time Tsth, the vehicle weight changes while the vehicle is stopped. It is determined that The estimated value MS of the vehicle weight is set to the initial value MS_Re. However, the condition that the elapsed time Ts is equal to or longer than the stoppage determination time Tsth can be satisfied not only when carrying a baggage into or out of a vehicle but also when waiting for a signal. When waiting for a signal, the vehicle weight may not change. In the present embodiment, when the vehicle restarts after stopping, such as when waiting for a signal, the vehicle weight does not change, the estimated value MS of the vehicle weight is quickly returned to the estimated value Ma before reset. Therefore, vehicle control using the estimated value MS of the vehicle weight as the control parameter can be appropriately performed even immediately after the vehicle restarts after the vehicle stops, such as waiting for a signal.

  (6) As the vehicle control using the estimated value MS of the vehicle weight as a control parameter, rollover suppression control is exemplified. In the present embodiment, the threshold value Gyth for specifying the start timing of the rollover suppression control is set to a smaller value when the vehicle weight estimation value MS is large than when it is small. Therefore, in a heavy vehicle, the rollover suppression control is started at an early timing, so that the vehicle can be prevented from rollover. On the other hand, in a light vehicle, it is suppressed that the rollover suppression control is started at a timing when the possibility of rollover is low. That is, inadvertent execution of the rollover suppression control can be suppressed. In particular, in this embodiment, the estimation accuracy of the estimated value MS of the vehicle weight after the vehicle restarts is improved. Therefore, even if it is immediately after the vehicle restarts, the rollover suppression control can be appropriately performed.

  (7) In recent years, the driver's awareness of the environment has increased. Therefore, when the vehicle is stopped for a relatively long time, such as when waiting for a signal, the ignition switch may be turned off voluntarily and the engine 11 may be stopped. Here, if the storage area 341 is provided in the RAM 33, the storage area 341 is initialized when the vehicle restarts, and a predetermined number Y of vehicles are used to obtain the normal estimated value Mave of the vehicle weight. It becomes necessary to recalculate the weight data M. In this case, a certain amount of time is required before the highly accurate estimation value MS of the vehicle weight can be obtained.

  In this regard, in the present embodiment, the storage area 341 is provided in the EEPROM 34. Therefore, even when the ignition switch is turned off when the vehicle is stopped, the vehicle weight normal estimated value Mave () is used by using each vehicle weight data M stored in the storage area 341 when the vehicle subsequently restarts. = Estimated value MS) can be calculated. Therefore, even when the ignition switch is turned off when the vehicle is stopped, the estimation accuracy of the estimated value MS of the vehicle weight after the subsequent restart can be improved.

The embodiment may be changed to another embodiment as described below.
In the embodiment, the stop condition may not include that the parking brake 25 is operated. In this case, the determination process of step S16 is omitted from the vehicle weight estimation process routine.

In the embodiment, the stoppage determination time Tsth may be any time other than “30 seconds” (for example, 20 seconds).
In the embodiment, the determination processes in steps S17 and S18 may be omitted from the vehicle weight estimation process routine. In this case, it is determined that the vehicle has stopped only when the parking brake 25 is operated.

  In the embodiment, when the vehicle is a vehicle with a power take-off device, the stop condition may include that the power take-off device is operating. Further, when the in-vehicle transmission 120 is an automatic transmission, the stop condition may include that the range of the transmission 120 is a parking range.

  In the embodiment, the normal estimated value Mave of the vehicle weight is acquired based on the predetermined number Y of vehicle weight data M calculated after the vehicle has started, and the normal estimated value Mave is updated during the subsequent driving of the vehicle. You don't have to.

Further, during the traveling of the vehicle, the normal estimated value Mave of the vehicle weight may be acquired based on the vehicle weight data M of the most recent predetermined number Y.
In the embodiment, a moving average between the normal estimated value of the vehicle weight acquired at the previous timing and the normal estimated value of the vehicle weight acquired at the current timing is calculated, and the final vehicle weight is calculated based on the calculation result. The normal estimated value Mave may be acquired.

In the embodiment, the gain value TH for setting the determination value Mth is an arbitrary value other than “0.3” (for example, 0.2) as long as it is a positive value of “0.5” or less. ).
In the embodiment, the determination value Mth may be a fixed value set in advance. In this case, the determination value Mth is preferably set to a value corresponding to the vehicle body weight of the vehicle on which the brake ECU 30 is mounted.

  In the embodiment, the predetermined number Z for calculating the provisional estimated value Mn is an arbitrary number other than “3” (for example, 5) as long as it is less than the predetermined value Y for obtaining the normal estimated value Mave. May be. The larger the predetermined number Z, the higher the accuracy of the provisional estimated value Mn. Therefore, the gain value TH for setting the determination value Mth may be a small value.

  In the embodiment, the predetermined number Y for calculating the normal estimated value Mave may be an arbitrary number other than “15” (for example, 10 or 20) as long as the normal estimated value Mave can be obtained with high accuracy. Good.

In the embodiment, the storage area 341 may be provided in the RAM 33.
In the embodiment, the drive torque F may be acquired using a characteristic map such as an engine torque map prepared in advance without using a sensor.

  -In embodiment, when calculating a parameter (wheel speed VW) based on the detection signal from a sensor (for example, wheel speed sensor SE3), a predetermined filter process is performed to the detection signal, and the signal after the filter process The parameter may be calculated based on the above. Further, a predetermined filter process may be performed on a parameter (wheel speed VW) calculated based on a detection signal from a sensor (for example, a wheel speed sensor SE3), and vehicle control may be performed using the parameter after the filter process. .

  The vehicle weight estimation apparatus of the present invention may be embodied by an in-vehicle ECU (for example, the engine ECU 14) other than the brake ECU 30. Of course, the vehicle may be provided with an ECU dedicated to the calculation of the estimated value MS of the vehicle weight.

  -In embodiment, you may set the threshold value Gyth for the start determination of rollover suppression control using a predetermined relational expression. The predetermined relational expression may be a linear function or a quadratic function that decreases the threshold value Gyth as the estimated value MS of the vehicle weight increases.

  In the embodiment, the estimated value MS of the vehicle weight may be used as a control parameter during engine control by the engine ECU 14. In addition, when the in-vehicle transmission 120 is an automatic transmission, the estimated value MS of the vehicle weight may be used as a control parameter at the time of shift control in the automatic transmission.

Next, technical ideas that can be grasped from the above embodiments and other embodiments will be added below.
(A) The vehicle weight data calculating means (30, S20) calculates vehicle weight data (M) using a vehicle body acceleration (Gx) of the vehicle.

  (B) The determination value setting means (30, S31) is a value less than half of the estimated value (Ma) of the vehicle weight before the determination value (Mth) is reset by the reset means (30, S27). A vehicle weight estimation apparatus, characterized by being set to:

  DESCRIPTION OF SYMBOLS 10 ... Wheel, 14 ... Engine ECU as an example of vehicle weight estimation apparatus, 25 ... Parking brake, 30 ... Vehicle weight estimation apparatus, Brake ECU (Example of vehicle weight data calculating means, No. 1) 1 estimation value acquisition means, lateral acceleration calculation means, threshold setting means, control means, stop determination means, reset means, second estimation value acquisition means, estimation value determination means, determination value setting means), M ... vehicle weight data, ΔM: Difference, Mave: Normal estimated value as a first estimated value of vehicle weight, Mn: Temporary estimated value as a second estimated value of vehicle weight, MS: Estimated value of vehicle weight, MS_Re: Initial value, Mth: Determination Value, Gx: longitudinal acceleration as vehicle acceleration, Gy: lateral acceleration, Gyth: threshold, Ts: elapsed time, Tsth: stop determination time, X: number of data, Y: predetermined number.

Claims (6)

Vehicle weight data calculating means (30, S20) for calculating vehicle weight data (M) for each preset period;
First estimated value acquisition means (30, S23) for acquiring a first estimated value (Mave) of the vehicle weight based on the calculated vehicle weight data (M) equal to or greater than the predetermined number (Y);
Stop determination means (30, S16, S17, S18) for determining whether or not a stop condition for determining that the vehicle is stopped;
Reset means (30, S27) for resetting an estimated value (MS) of the vehicle weight to an initial value (MS_Re) when it is determined that the stop condition is satisfied;
Based on vehicle weight data (M) less than the predetermined number (Y) calculated by the vehicle weight data calculation means (30, S20) after the vehicle starts when the vehicle starts after the stop condition is satisfied, Second estimated value acquisition means (30, S29) for acquiring a second estimated value (Mn) of weight;
When the vehicle starts after the stop condition is satisfied, the second estimated value (Mn) of the vehicle weight acquired by the second estimated value acquisition means (30, S29) and the second before the stop condition is satisfied The determination that the difference (ΔM) from the first estimated value (Mave, Ma) of the vehicle weight acquired by the 1 estimated value acquiring means (30, S23) is set as a criterion for determining whether or not the vehicle weight has changed. If it is less than the value (Mth), the estimated value determining means (30,) returns the estimated value (MS) of the vehicle weight from the initial value (MS_Re) to the first estimated value (Mave, Ma) of the vehicle weight. S33), a vehicle weight estimation device. The estimated value determining means (30, S27, S33)
When the difference (ΔM) is equal to or greater than the determination value (Mth),
When the number (X) of vehicle weight data (M) calculated by the vehicle weight data calculation means (30, S20) after the start of the vehicle is less than the predetermined number (Y), an estimated value of vehicle weight (MS ) At the initial value (MS_Re),
When the data number (X) of the vehicle weight data (M) calculated after the vehicle starts is equal to or greater than the predetermined number (Y), the estimated value (MS) of the vehicle weight is obtained as the first estimated value acquisition means (30 The vehicle weight estimation apparatus according to claim 1, wherein the vehicle weight estimation apparatus obtains a first estimated value (Mave) of the vehicle weight acquired in S23).   Determination value setting means for setting the determination value (Mth) to a larger value than when the estimated value (MS, Ma) of the vehicle weight before being reset by the reset means (30, S27) is large. The vehicle weight estimation apparatus according to claim 1, further comprising (30, S31). The stop condition is:
Braking force is applied to the wheel (10) by the parking brake (25) of the vehicle,
And the elapsed time (Ts) from when the vehicle stops is equal to or greater than a preset stop determination time (Tsth). The vehicle weight estimation apparatus according to any one of the above. A vehicle rollover suppression device that performs rollover suppression control that suppresses vehicle rollover,
The vehicle weight estimating device (14, 30) according to any one of claims 1 to 4,
Lateral acceleration calculation means (30, S41) for calculating the lateral acceleration (Gy) of the vehicle;
Wherein the threshold value (Gyth) for specifying a start timing of the rollover prevention control, than the when the vehicle weight estimation device vehicle weight estimation value calculated by the (14,30) (MS) is large is small Threshold setting means (30, S42) for setting a small value;
When the lateral acceleration (Gy) acquired by the lateral acceleration calculating means (30, S41) is equal to or greater than the threshold (Gyth) set by the threshold setting means (30, S42), the rollover suppression control is performed. Control means (30, S44) for starting the vehicle. Vehicle weight data calculating step (S20) for calculating vehicle weight data (M) for each preset period;
A first estimated value acquisition step (S23) for acquiring a first estimated value (Mave) of the vehicle weight based on the calculated vehicle weight data (M) equal to or greater than the predetermined number (Y);
A stop determination step (S16, S17, S18) for determining whether or not a stop condition for determining that the vehicle has stopped is satisfied;
A reset step (S27) for resetting an estimated value (MS) of the vehicle weight to an initial value (MS_Re) when it is determined that the stop condition is satisfied;
When the vehicle starts after the stop condition is satisfied, a second vehicle weight data (M) less than the predetermined number (Y) calculated in the vehicle weight data calculation step (S20) after the vehicle starts is set. A second estimated value acquisition step (S29) for acquiring an estimated value (Mn);
When the vehicle starts after the stopping condition is satisfied, the second estimated value (Mn) of the vehicle weight acquired in the second estimated value acquiring step (S29) and the first estimated value acquisition before the stopping condition is satisfied. The difference (ΔM) from the first estimated value (Mave, Ma) of the vehicle weight acquired in step (23) is less than the determination value (Mth) set as a criterion for determining whether or not the vehicle weight has changed. In this case, an estimated value determining step (S34) for returning the estimated value (MS) of the vehicle weight from the initial value (MS_Re) to the first estimated value (Mave, Ma) of the vehicle weight. A characteristic vehicle weight estimation method.

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