KR102749927B1 - Electric vehicle braking control method and system - Google Patents

Abstract

A method and system for replacing variable deceleration due to dynamic regenerative braking of an electric vehicle according to its own vehicle state with constant deceleration are provided. The electric vehicle braking control method according to an embodiment of the present invention includes the steps of: obtaining, by an electric vehicle braking control system installed in an electric vehicle capable of performing a one-pedal driving mode, specification information and status information of the vehicle; calculating and storing, by the electric vehicle braking control system, a reference deceleration braking torque value based on the obtained information; and determining, by the electric vehicle braking control system, whether to automatically control the deceleration braking torque based on the stored reference deceleration braking torque value when the electric vehicle is in a braking state while driving. Accordingly, dynamic deceleration that occurs due to surrounding variables during deceleration by regenerative braking alone can be uniformly induced to decelerate based on a tabulated torque value, thereby ensuring driving stability of a driver.

Description

{Electric vehicle braking control method and system}

The present invention relates to a method and system for controlling the braking of an electric vehicle, and more specifically, to a method and system for replacing variable deceleration due to fluid regenerative braking according to the vehicle status of an electric vehicle with constant deceleration.

One-pedal driving, supported by most electric vehicles, is a method of driving using only one accelerator pedal by utilizing the regenerative braking system.

The regenerative braking system can automatically control the regenerative braking stage according to the road slope and driving conditions of the vehicle ahead while driving, thereby minimizing unnecessary brake and accelerator pedal operation.

Electric vehicles that can perform one-pedal driving mode by applying such a regenerative braking system have a problem in that the risk of vehicle collision increases because the amount of regenerative braking can change dynamically depending on the vehicle's condition, such as the vehicle's battery, speed, driving direction (angle), and regenerative braking intensity.

For example, electric vehicles that can perform one-pedal driving mode by applying a regenerative braking system have a problem that the risk of vehicle collision increases when the battery temperature is low or fully charged, when the amount of regenerative braking is insufficient and the amount of deceleration varies, or when the vehicle does not decelerate as much as the driver expects when driving on a very steep slope.

Therefore, it is necessary to find a way to replace the variable deceleration of a vehicle, which can vary depending on the vehicle's battery, speed, driving direction (angle), and regenerative braking intensity, with a deceleration of a constant intensity.

delete

Korean Patent Registration No. 10-2387130 (Title of invention: Electric vehicle braking operation system)

The present invention has been made to solve the above problems, and the purpose of the present invention is to provide an electric vehicle braking control method and system capable of ensuring driving stability of a driver by evenly inducing deceleration based on a tabulated torque value from a fluid deceleration that occurs due to surrounding variables during deceleration using only regenerative braking.

In order to achieve the above object, according to one embodiment of the present invention, a method for controlling braking in an electric vehicle includes: a step in which an electric vehicle braking control system installed in an electric vehicle capable of performing a one-pedal driving mode acquires specification information and status information of the vehicle; a step in which the electric vehicle braking control system calculates and stores a reference deceleration braking torque value based on the acquired information; and a step in which, when the electric vehicle is in a braking state while driving, the electric vehicle braking control system determines whether to automatically control deceleration braking torque based on the stored reference deceleration braking torque value.

And the step of calculating and storing the reference deceleration braking torque value is to measure the reference deceleration braking torque value based on a case where regenerative braking deceleration occurs with the same accelerator pressure for a certain period of time during deceleration after accelerating straight up to a certain speed on a flat road surface, and then classify and tabulate the data according to the vehicle specification information and the pressure applied to the accelerator.

In addition, the step of calculating and storing the reference deceleration braking torque value can perform data measurement work for the reference deceleration braking torque value after confirming whether the battery installed in the vehicle is capable of 100% regenerative braking.

And the vehicle specification information may include information about the vehicle's weight and wheel size, and the vehicle's status information may include information about the battery status, speed, steering angle, horizontal status, accelerator pressure level, and regenerative braking status.

In addition, the step of determining whether to automatically control the deceleration braking torque can determine whether to automatically control in all states except when the automatic deceleration of the electric vehicle is disabled, when the regenerative braking reference torque value for the accelerator pressure value during deceleration is not in the stored torque value table, and when the vehicle is stopped.

And the step of determining whether or not to automatically control the deceleration braking torque can be configured such that, when determining whether or not to automatically control the deceleration braking torque, a deceleration torque value according to the deceleration speed in real time is calculated, and if it is lower than the stored reference deceleration braking torque value, an automatic control mode of the deceleration braking torque for deceleration is performed.

In addition, the step of determining whether or not to automatically control the deceleration braking torque may be such that, when the automatic control mode of the deceleration braking torque is performed, the pressure value of the excel stored in the lookup table, the speed before deceleration, the deceleration braking torque value, the moving distance during the deceleration time, and the deceleration time are reflected so that the deceleration braking torque reaches the reference deceleration braking torque value, and the deceleration braking torque value through the brake is added to the deceleration braking torque.

And the deceleration torque value according to the real-time deceleration speed can be calculated by referring to the following Equation 2, where the weight of the vehicle is W, the deceleration rate (D) is V1, the speed of the vehicle immediately before deceleration is V2, the speed decelerated only by regenerative braking with a constant accelerator pressure from speed V1 is T, and the time taken to go from speed V1 to speed V2 is T.

(Formula 1) Deceleration torque value = W*D*S

(Formula 2) D = V/T = ((V1/(60sec*60min)) - (V2/(60sec*60min)))/T

In addition, the step of determining whether or not to automatically control the deceleration braking torque may be performed by calculating the travel distance and the deceleration torque value for the first second of deceleration when the electric vehicle is in a braking state while driving, and if it is lower than the stored reference deceleration braking torque value, the automatic control mode of the deceleration braking torque may be performed for the remaining time excluding the first second of the deceleration time.

Meanwhile, according to another embodiment of the present invention, an electric vehicle braking control system comprises: an information collection unit installed in an electric vehicle capable of performing a one-pedal driving mode, which obtains vehicle specification information and status information; a processor which calculates and stores a reference deceleration braking torque value based on the information obtained through the information collection unit, and determines whether to automatically control the deceleration braking torque based on the stored reference deceleration braking torque value when the electric vehicle is in a braking state while driving; and a storage unit in which the reference deceleration braking torque value calculated by the processor is stored.

As described above, according to embodiments of the present invention, the driving stability of the driver can be secured by evenly inducing deceleration based on a tabulated torque value rather than the fluid deceleration that occurs due to surrounding variables during deceleration using only regenerative braking.

Figure 1 is a drawing provided for the description of an electric vehicle braking control system according to one embodiment of the present invention;
Figure 2 is a drawing provided for explaining an electric vehicle braking control method according to one embodiment of the present invention.
FIG. 3 is a drawing providing a more detailed description of a process for calculating a reference deceleration braking torque value based on information acquired according to one embodiment of the present invention and storing the same in a lookup table; and
FIG. 4 is a drawing provided for a more detailed description of a process for determining whether to automatically control deceleration braking torque according to one embodiment of the present invention.

Hereinafter, the present invention will be described in more detail with reference to the drawings.

FIG. 1 is a drawing provided to explain an electric vehicle braking control system according to one embodiment of the present invention.

The electric vehicle braking control system according to the present embodiment is installed in an electric vehicle capable of performing a one-pedal driving mode, and can induce even deceleration based on a tabulated torque value by adding a deceleration braking torque value through the brake to the fluid deceleration that occurs due to surrounding variables when decelerating only by regenerative braking.

To this end, the electric vehicle braking control system includes an information collection unit (110), a processor (120), and a storage unit (130).

The information collection unit (110) is provided to obtain vehicle specification information and status information.

For example, the information collection unit (110) may include a communication module that is connected to the outside through CAN communication, etc., and can receive vehicle specification information and status information necessary for the processor (120) to operate, and an input interface that can directly input vehicle specification information and status information.

Here, the vehicle specification information may include information about the vehicle's weight and wheel size, and the vehicle's status information may include information about the battery status, speed, steering angle, horizontal status, accelerator pressure level, and regenerative braking status.

The storage unit (130) is a storage medium that stores data and programs necessary for the processor (120) to operate.

For example, the storage unit (130) may store a standard deceleration braking torque value, an accelerator pressure value, a speed before deceleration, a deceleration braking torque value, a moving distance during deceleration time, a deceleration time, etc., which are calculated and tabulated by the processor (120).

The processor (120) is provided to process all matters of the electric vehicle braking control system.

For example, the processor (120) can calculate a reference deceleration braking torque value based on information acquired through the information collection unit and store the value in the storage unit.

And, when the electric vehicle is in a braking state while driving, the processor (120) can determine whether to automatically control the deceleration braking torque based on the stored reference deceleration braking torque value.

And the processor (120) can evenly induce deceleration of the electric vehicle based on the tabulated torque value by adding a deceleration braking torque value through the brake to the fluid deceleration (deceleration braking torque through regenerative braking) that occurs due to surrounding variables during deceleration only through regenerative braking.

That is, when the processor (120) performs the automatic control mode, the processor controls the brake so that the deceleration braking torque of the electric vehicle reaches the reference deceleration braking torque value based on information stored in the lookup table (e.g., pressure value of the accelerator, speed before deceleration, deceleration braking torque value, moving distance during deceleration time, deceleration time, etc.), thereby allowing the unbalanced moving distance of the electric vehicle to be adjusted to the moving distance during the deceleration time stored in the lookup table when decelerating only by regenerative braking.

FIG. 2 is a drawing provided to explain an electric vehicle braking control method according to one embodiment of the present invention.

The electric vehicle braking control method according to the present embodiment can be executed by the electric vehicle braking control system described above with reference to FIG. 1.

Referring to FIG. 2, the electric vehicle braking control method can obtain vehicle specification information and status information through an information collection unit (S210), calculate a reference deceleration braking torque value based on the obtained information (S220), and store this in a lookup table (S230).

For example, a method for controlling the braking of an electric vehicle can classify and tabulate data on a reference deceleration braking torque value measured based on a case where regenerative braking deceleration occurs with the same accelerator pressure for a certain period of time after accelerating straight up to a certain speed on a flat road surface and then decelerating, according to vehicle specification information and the pressure applied to the accelerator.

That is, the measured reference deceleration braking torque value can be classified by pressure applied to the accelerator based on vehicles with the same vehicle weight and wheel size and stored in a lookup table.

Here, items recorded in the lookup table may include the pressure value of Excel, the speed before deceleration, the deceleration braking torque value, the distance traveled during the deceleration time, and the deceleration time.

And, the electric vehicle braking control method can determine whether to automatically control the deceleration braking torque based on the stored reference deceleration braking torque value when the electric vehicle is in a braking state while driving (S240), thereby performing the automatic control mode of the deceleration braking torque.

Here, the deceleration braking torque basically means the deceleration braking torque through regenerative braking before the automatic control mode is performed, and when the automatic control mode is performed, the deceleration braking torque value through the brake is added to the deceleration braking torque value through regenerative braking, so that the total deceleration braking torque value for decelerating the electric vehicle can reach the reference deceleration braking torque value.

In summary, the electric vehicle braking control system according to the present embodiment performs an automatic control mode of the deceleration braking torque when the deceleration braking torque value through regenerative braking is insufficient compared to the reference deceleration braking torque value stored in the lookup table, thereby adding the deceleration braking torque through the brake to the deceleration braking torque through regenerative braking, thereby allowing the vehicle to decelerate to a stable torque value (a torque value identical to the stored reference deceleration braking torque value).

FIG. 3 is a diagram provided for a more detailed description of a process for calculating a reference deceleration braking torque value based on information acquired according to one embodiment of the present invention and storing the same in a lookup table.

Referring to FIG. 3, the electric vehicle braking control system can calculate a reference deceleration braking torque value and store it in a lookup table when a preset measurement criterion is satisfied (S310-Yes).

For example, an electric vehicle brake control system may measure data on a reference deceleration braking torque value when all of criteria a) through f) are satisfied by considering whether a) the vehicle is in an abnormal state, b) whether it is in one-pedal driving mode, c) whether the vehicle is on level ground through the vehicle's level, d) whether the vehicle angle (steering angle) is aligned and in a straight line, e) whether the battery installed in the vehicle is capable of 100% regenerative braking, and f) whether the vehicle weight/wheel size is input.

Specifically, the electric vehicle brake control system determines whether the vehicle is in a regenerative braking deceleration state due to a constant accelerator pressure (S320) if the preset measurement criteria are satisfied (S310-Yes), and if the vehicle is in a regenerative braking deceleration state due to a constant accelerator pressure (S320-Yes), and calculates a reference deceleration braking torque value by collecting the vehicle status information until the vehicle decelerates to a constant speed section or reaches a stop state (S330-Yes) (S340), and classifies the calculated reference deceleration braking torque value according to the vehicle specification information and the pressure applied to the accelerator and stores it in a lookup table (S350).

FIG. 4 is a drawing provided for a more detailed description of a process for determining whether to automatically control deceleration braking torque according to one embodiment of the present invention.

Referring to FIG. 4, the electric vehicle braking control system can determine whether to automatically control the deceleration braking torque based on the stored reference deceleration braking torque value when a preset judgment criterion is satisfied (S410-Yes).

For example, an electric vehicle braking control system can determine whether to perform automatic control in all states except when the automatic braking of the electric vehicle is disabled and the regenerative braking reference torque value for the accelerator pressure value during deceleration is not stored in the torque value table (lookup table) and when the vehicle is stopped.

Specifically, the electric vehicle braking control system can determine whether to automatically control the deceleration braking torque based on the stored reference deceleration braking torque value when the electric vehicle is in an abnormal state where the battery cannot operate in a regenerative braking state while braking during driving or when the battery cannot perform 100% regenerative braking.

Meanwhile, the electric vehicle braking control system calculates a deceleration torque value according to a real-time deceleration speed when a preset judgment criterion is satisfied (S410-Yes), and when the calculated deceleration torque value is lower than a stored reference deceleration braking torque value (S430-Yes), it can notify the vehicle of a situation requiring deceleration and/or cause an automatic control mode of the deceleration braking torque for deceleration to be performed (S440).

For example, an electric vehicle braking control system may calculate a travel distance and a deceleration torque value for the first second of deceleration when the electric vehicle is in a braking state while driving, and if the value is lower than the stored reference deceleration braking torque value, notify the vehicle of a situation in which deceleration is necessary, and/or perform an automatic control mode of the deceleration braking torque for the remaining time excluding the first second during the deceleration time.

Here, the automatic control mode is a mode that adds a deceleration braking torque value through the brake to the deceleration braking torque so that the deceleration braking torque reaches the reference deceleration braking torque value by considering the pressure value of the accelerator, the speed before deceleration, the deceleration braking torque value, the moving distance during the deceleration time, the deceleration time, etc. as described above.

For example, if an electric vehicle brake control system cannot decelerate to 60 km/h in 1 second but instead decelerates to 62 km/h (V0) due to reasons such as insufficient battery regenerative braking or a change in vehicle weight when a reference output information value exists and deceleration starts based on that reference value, the distance traveled in 1 second is 19.72 m, so the remaining travel distance (L) of 13.52 m is decelerated in 1 second, and accordingly, a changed speed (V1) that can travel only that distance is required.

V1 = 2*Va-V0

Va = 13.52/1sec

Va = 13.52m/s

V1 = 2*13.52

V0 (distance traveled per second at 62 km/h) = 62/3600 = 17.22 m/s

V1 = 27.04 - 17.22 = 9.82m/s

Accordingly, the electric vehicle braking control system can perform brake control to decelerate the vehicle to approximately 35 km/h (9.82*3600) during the remaining deceleration calculation time (1 second) after 1 second by executing automatic control mode.

Here, the process of calculating the deceleration movement distance through the deceleration rate is briefly explained as follows.

The total deceleration time is 2 seconds, and if the speed changes from 80 km/h (V0) to 60 km/h (V1) at 1 second after deceleration (the point reached after deceleration for 1 second), the deceleration rate is ((80000/3600) - (60000/3600)) = 22.22, and the acceleration is 5.56 m/s2 (A) because it is the change in speed over the changed time.

And the distance traveled during the first second after deceleration is 19.44m, and if the speed becomes 40km/h at the 2nd second point after deceleration, the distance traveled from the 1st second point to the 2nd second point is 13.8m, and the total distance traveled during the 2nd second after deceleration is 33.24m.

Here, the electric vehicle braking control system can store only the calculated total deceleration movement distance (33.24 m) and deceleration time (2 seconds) in the lookup table. This is to minimize the data stored in the lookup table, thereby reducing the resources and processing time required to process it.

Meanwhile, as described above, when the electric vehicle braking control system performs the automatic control mode of the deceleration braking torque, it can adjust the real-time deceleration braking torque value of the electric vehicle to reach the stored reference deceleration braking torque value by adding the deceleration torque value through the brake to the deceleration braking torque value through regenerative braking.

The real-time deceleration braking torque value according to the real-time deceleration speed can be calculated by referring to the following Equation 1 when the weight of the vehicle is W, the deceleration rate is D, and the radius of the wheel is S.

At this time, the deceleration rate (D) can be calculated by referring to Equation 2 below, where the speed of the vehicle immediately before deceleration is V1, the speed decelerated from the V1 speed by regenerative braking alone with a constant accelerator pressure is V2, and the time taken to go from the V1 speed to the V2 speed is T.

(Formula 1) Deceleration torque value = W*D*S

(Formula 2) D = V/T = ((V1/(60sec*60min)) - (V2/(60sec*60min)))/T

For example, an electric vehicle brake control system can calculate a deceleration rate by setting a preset time unit (e.g., 1 second) as T, the time taken to go from speed V1 to speed V2, when the vehicle is decelerated from a constant speed using only regenerative braking, and can calculate a deceleration torque value using the calculated deceleration rate and the input values of the vehicle weight and wheel radius.

Specifically, for example, if a vehicle decelerates from 80 km/h to 60 km/h after 2 seconds of deceleration using only regenerative braking, the distance traveled per second changes from 22.22 m/s to 16.66 m/s, so the deceleration rate is calculated as 5.56, and the deceleration torque value can be calculated as W (2000 kg) * 5.56 * S (0.25 m) = 2780 NM.

This allows the travel distance of an unbalanced electric vehicle to be adjusted to the travel distance during the deceleration time stored in the lookup table when decelerating using regenerative braking alone.

Meanwhile, it goes without saying that the technical idea of the present invention can be applied to a computer-readable recording medium storing a computer program that performs the functions of the device and method according to the present embodiment. In addition, the technical idea according to various embodiments of the present invention can be implemented in the form of a computer-readable code recorded on a computer-readable recording medium. The computer-readable recording medium can be any data storage device that can be read by a computer and store data. For example, the computer-readable recording medium can be a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, an optical disk, a hard disk drive, etc. In addition, the computer-readable code or program stored on the computer-readable recording medium can be transmitted through a network connected between computers.

In addition, although the preferred embodiments of the present invention have been illustrated and described above, the present invention is not limited to the specific embodiments described above, and various modifications may be made by a person skilled in the art without departing from the gist of the present invention as claimed in the claims. Furthermore, such modifications should not be individually understood from the technical idea or prospect of the present invention.

110: Information Collection Department
120 : Processor
130 : Storage

Claims (10)

A step for obtaining vehicle specification information and status information by an electric vehicle braking control system installed in an electric vehicle capable of performing one-pedal driving mode;
A step of the electric vehicle brake control system calculating and storing a reference deceleration braking torque value based on the acquired information; and
When the electric vehicle is in a braking state while driving, the electric vehicle braking control system includes a step of determining whether to automatically control the deceleration braking torque based on the stored reference deceleration braking torque value;
The step of calculating and storing the standard deceleration braking torque value is:
The data on the standard deceleration braking torque value measured based on the case where regenerative braking deceleration occurs with the same accelerator pressure for a certain period of time after accelerating straight up to a certain speed on a flat road surface is classified and tabulated according to the vehicle's specification information and the pressure applied to the accelerator.
The step of calculating and storing the standard deceleration braking torque value is:
After confirming whether the battery installed in the vehicle is capable of 100% regenerative braking, data measurement for the standard deceleration braking torque value is performed.
The vehicle's specifications are:
Contains information about the vehicle's weight and wheel size.
The vehicle's status information is:
It contains information about battery status, speed, steering angle, level, accelerator pressure, and regenerative braking status.
The step for determining whether to automatically control the deceleration braking torque is:
In cases where the automatic deceleration of the electric vehicle is disabled and the regenerative braking reference torque value for the accelerator pressure value is not in the torque value table stored during deceleration, and in cases where the vehicle is stopped, it determines whether automatic control is performed in all other states.
The step for determining whether to automatically control the deceleration braking torque is:
When determining whether to automatically control the deceleration braking torque, the deceleration torque value according to the deceleration speed in real time is calculated, and if it is lower than the stored reference deceleration braking torque value, the automatic control mode of the deceleration braking torque is performed.
The step for determining whether to automatically control the deceleration braking torque is:
When performing the automatic control mode of the deceleration braking torque, the pressure value of the excel stored in the lookup table, the speed before deceleration, the deceleration braking torque value, the moving distance during the deceleration time, and the deceleration time are reflected so that the deceleration braking torque reaches the reference deceleration braking torque value, and the deceleration braking torque value through the brake is added to the deceleration braking torque.
The deceleration torque value according to the real-time deceleration speed is
If the weight of the vehicle is W, the deceleration rate is D, and the radius of the wheel is S, it is calculated by referring to the following equation 1,
The deceleration rate (D) is
If the speed of the vehicle just before deceleration is V1, the speed decelerated from V1 speed to V2 by regenerative braking with a constant accelerator pressure, and the time taken to go from V1 speed to V2 speed is T, it is calculated by referring to the following formula 2,
The step for determining whether to automatically control the deceleration braking torque is:
A method for controlling braking of an electric vehicle, characterized in that when an electric vehicle is in a braking state while driving, the distance traveled and the deceleration torque value for the first second of deceleration are calculated, and if it is lower than the stored reference deceleration braking torque value, the automatic control mode of the deceleration braking torque is performed for the remaining time excluding the first second of the deceleration time.
(Formula 1) Deceleration torque value = W*D*S
(Formula 2) D = V/T = ((V1/(60sec*60min)) - (V2/(60sec*60min)))/T
delete delete delete delete delete delete delete delete An information collection unit installed in an electric vehicle capable of performing one-pedal driving mode, which obtains vehicle specification information and status information;
A processor that calculates and stores a reference deceleration braking torque value based on information acquired through an information collection unit, and determines whether to automatically control the deceleration braking torque based on the stored reference deceleration braking torque value when the electric vehicle is in a braking state while driving; and
A storage unit in which a reference deceleration braking torque value produced by the processor is stored;
The processor is,
The data on the standard deceleration braking torque value measured based on the case where regenerative braking deceleration occurs with the same accelerator pressure for a certain period of time after accelerating straight up to a certain speed on a flat road surface is classified and tabulated according to the vehicle's specification information and the pressure applied to the accelerator.
The processor is,
After confirming whether the battery installed in the vehicle is capable of 100% regenerative braking, data measurement for the standard deceleration braking torque value is performed.
The vehicle's specifications are:
Contains information about the vehicle's weight and wheel size.
The vehicle's status information is:
It includes information about battery status, speed, steering angle, level, accelerator pressure, and regenerative braking status.
The processor is,
In cases where the automatic deceleration of the electric vehicle is disabled and the regenerative braking reference torque value for the accelerator pressure value is not in the torque value table stored during deceleration, and in cases where the vehicle is stopped, it determines whether automatic control is performed in all other states.
The processor is,
When determining whether to automatically control the deceleration braking torque, the deceleration torque value according to the deceleration speed in real time is calculated, and if it is lower than the stored reference deceleration braking torque value, the automatic control mode of the deceleration braking torque is performed.
The processor is,
When performing the automatic control mode of the deceleration braking torque, the pressure value of the excel stored in the lookup table, the speed before deceleration, the deceleration braking torque value, the moving distance during the deceleration time, and the deceleration time are reflected so that the deceleration braking torque reaches the reference deceleration braking torque value, and the deceleration braking torque value through the brake is added to the deceleration braking torque.
The deceleration torque value according to the real-time deceleration speed is
If the weight of the vehicle is W, the deceleration rate is D, and the radius of the wheel is S, it is calculated by referring to the following equation 1,
The deceleration rate (D) is
If the speed of the vehicle just before deceleration is V1, the speed decelerated from V1 speed to V2 by regenerative braking with a constant accelerator pressure is V2, and the time taken to go from V1 speed to V2 speed is T, it is calculated by referring to the following formula 2,
The processor is,
An electric vehicle braking control system characterized in that, when an electric vehicle is in a braking state while driving, the distance traveled and the deceleration torque value for the first second of deceleration are calculated, and if it is lower than the stored reference deceleration braking torque value, the automatic control mode of the deceleration braking torque is performed for the remaining time excluding the first second of the deceleration time.
(Formula 1) Deceleration torque value = W*D*S
(Formula 2) D = V/T = ((V1/(60sec*60min)) - (V2/(60sec*60min)))/T