RU2810955C1 - Device for determining the main resistance to movement of freight cars - Google Patents

Abstract

FIELD: railway transport.

SUBSTANCE: device for determining the main resistance to movement of a freight car contains a brake activation device (6), connected to a battery, including brake hoses, an electromagnetic valve for releasing air from the brake line with a radio-controlled relay and a backup time relay. To change the time, distance travelled and speed of movement, a navigation receiver (4) is used, mounted on the car under test (1), connected to a computer (5).

EFFECT: invention improves the accuracy of measurements when determining the main resistance to movement of freight cars in a train.

1 cl, 6 dwg

Description

The inventions relate to railway transport, in particular to devices for determining the main resistance to movement of rolling stock.

There is a known method for determining the main resistance to movement of a self-propelled rolling stock - the method of equilibrium speeds (variants) (RU No. 2723132, G01M 17/08, B61K 9/08, publ. 06/08/2020), which consists in measuring the dynamometer force on a straight section of the railway track traction, speed of movement and calculation of tangential traction force, while the dependence of the main resistance to movement on the speed of movement is taken in advance for a similar type of self-propelled rolling stock, acceleration of a unit of self-propelled rolling stock is performed sequentially at a number of positions of the driver’s controller with the control of automatic transition from one position of the driver’s controller turned off to another on sections of the railway track with a zero slope until the unit of self-propelled rolling stock reaches the equilibrium speed of movement, determined by the absence of acceleration, the values of the tangential traction force are fixed, equal to the force of the main resistance to movement as a cart; based on the obtained values of the main resistance to movement as a cart, a dependence of the main resistance is constructed movement as a cart on speed, recalculate the tangential traction force by replacing the previously accepted values of the main resistance to movement with values calculated from the experimentally obtained dependence, using the newly obtained values of the tangential traction force, construct a new dependence of the main resistance to movement as a cart on the speed of the self-propelled rolling stock, repeat the iterative process until the required accuracy of the dependence of the main resistance to movement of a cart is obtained.

The disadvantage of this method is that when used for testing, the determined resistance to movement of the car will additionally contain frontal aerodynamic drag or tail aerodynamic drag if the locomotive is located behind or in front of the car in the direction of travel, respectively. In addition, it seems difficult to determine the absence of acceleration due to the significant influence of even small acceleration values on the determination of motion resistance.

There is a known dynamometer method for experimentally determining the main resistance (Proceedings of the All-Union Scientific Research Institute of Railway Transport. Issue 311. P.N. Astakhov. Resistance to the movement of railway rolling stock. M. Transport. 1966, pp. 41-63), according to which on a straight line On a section of track with a zero slope, the resistance to movement of a group of cars is measured using a dynamometer car located between the locomotive and the group of cars. The traction force measured by the dynamometer will correspond to the resistance force to the movement of the train. The resistance force to the movement of one car is determined by dividing it by the number of cars in the train. Resistivity is often determined by dividing the measured drag force by the mass of the composition.

According to the order of the Ministry of Transport of Russia dated October 23, 2017 No. 457 “On approval of the methodology for assessing the economic efficiency of operating freight innovative cars on the railway infrastructure of railways” using this method, when testing, the train must contain at least 65 conditional cars, and the train must be tested empty and loaded condition. During the experimental trips, the traction force on the automatic coupler, the speed of movement and the coordinates of the path are continuously recorded. Registration frequency is at least once per second. Measurements are carried out over the entire range of permissible speeds in increments of no more than 20 km/h.

In order to achieve comparable test results, trips are carried out using one series of locomotives. During testing, at least two and no more than five experimental trips are carried out.

When carrying out calculations they accept; that the main specific resistance to movement within each speed interval is a constant value and can be calculated by the expression:

where ƒ _Dsr is the specific average value of the dynamometer traction force on the selected section of the route (determined by the formula ƒ _Dsr =F _Dsr /Q, where F _Dsr is the average value of the dynamometer traction force on the selected section of the route, N; Q is the mass of the train, t), N/t;

_Wi is the resistance to movement from the slope (determined by the formula w _i =i⋅g, where i is the slope, ‰, g is the acceleration of gravity (9.81 m/s ² ). The numerical value of w _i is included in this equation with a sign “minus” on ascents and with a “plus” sign on descents), N/t;

w _r - resistance to movement from curves (determined by the formula w _r =6870/R, where R is the radius of the curve, m), N/t;

γ - coefficient equal to the ratio of the masses of the rotating parts of the car to the entire mass of the car;

a is the acceleration of the train, m/s ² .

The main specific resistance to movement of the evaluated cars is determined by the formula:

Where - the main specific resistance of the car being evaluated;

a ^OTs , b ^OTs , c ^OTs - respectively, the coefficients of the approximating dependence of the values of the main specific resistance to movement averaged over speed intervals for the cars being evaluated; V - train speed, km/h.

The disadvantages of this method are the low accuracy of measurements due to constant changes in the dynamometer traction force caused by longitudinal vibrations of the cars in the train, and the high cost of testing due to the need to exclude 65 cars from commercial operation, the need to rent cargo to load 65 cars, and carry out the loading and unloading.

A device is known for recording train movement parameters (RU No. 2041100, B61L 25/02, publ. 08/09/1995), containing a path and speed sensor connected to the input of the block for determining the distance traveled and to one input of the block for determining the speed, the output connected to one of recorder inputs, another input connected to the pressure sensor in the brake line, and the third input with the output of the block for determining the current time, the input of which is connected to a time stamp sensor connected to the second input of the speed determination block, equipped with a threshold element, an element for setting the manual control mode, a logical an AND element and a logical OR element, the output connected to the fourth input of the recorder, one input with the output of the block for determining the distance traveled, and the other input with the output of the logical element AND, the inputs of which are connected to the time stamp sensor, the output of the manual control mode setting element and the output of the threshold element , the input of which is connected to the output of the speed determination block.

The disadvantage of this device is the inability to determine the longitudinal acceleration necessary to calculate the resistance to movement.

A device is known for implementing a method for determining the specific resistance to movement of rolling stock (SU No. 914381, B61L 17/00, publ. 03.23.1982), equipped with an analog-to-digital converter and a calculation unit connected in series, the output of which is connected to an information output unit, and a measurement unit and recording motion parameters consists of an accelerometer installed on unsprung structures of the rolling stock, the axis of which is oriented along the track, an amplifier and a filter, through which the accelerometer is connected to an analog-to-digital converter, and a wheel speed indicator with a control pulse former connected to an analog-to-digital converter.

The disadvantage of this device is the high requirements for the measuring equipment included in the device, since when using it to implement the method for determining the specific resistance to the movement of rolling stock, it is necessary to carry out direct measurements of the acceleration value of the order of 0.001-0.002 g under conditions of strong dynamic and electromagnetic interference, which is practically unattainable using known accelerometers. The recorded acceleration is less than the measurement error of known accelerometers. Therefore, it is proposed to use it at low speeds when rolling cars along large slopes on hump yards.

There is a known method of rolling and a device for determining the main resistance to movement (Proceedings of the All-Union Scientific Research Institute of Railway Transport. Issue No. 311. P.N. Astakhov. Resistance to movement of railway rolling stock. M. Transport. 1966, pp. 63-71), accepted as a prototype. The method consists in the fact that the test object (train or self-propelled rolling stock) accelerates, then on a pre-selected straight section of track with known slopes, the engines are turned off, and the rolling stock rolls down under the influence of kinetic energy accumulated during acceleration, gradually slowing down. The degree of deceleration determines the force of resistance to the movement of a train or self-propelled rolling stock.

A device for determining the main resistance to movement is placed on a locomotive or laboratory car. The device includes a precision time measurement device (chronograph), a recording device in the form of a tape mechanism with paper tape, and a special contactor for marking pickets and kilometer posts. During testing, precise time stamps and the passage of markers along the track are recorded on paper tape, and then processed to calculate the acceleration of the decelerating rolling stock. The theoretical basis for determining the resistance to movement is the expression

where w _k is the specific resistance to movement;

i - path slope;

γ - coefficient taking into account the influence of rotating wheelsets;

V - speed;

t - time;

1000 - conversion factor from tons to kilograms;

- acceleration of the tested object.

However, the direct magnitude of the acceleration of the test object is not determined. Based on chronograph time stamps and manual markers of the passage of pickets and kilometer posts, the dependence of the distance traveled on time is determined. Subsequently, the magnitude of the acceleration is determined by double differentiation of the resulting dependence of the distance traveled on time. The slope value is taken from the path leveling tables. After passing the test section, the train or self-propelled vehicle is braked by the driver and stopped. The experiments are repeated several times, with the test unit of rolling stock being given different initial speeds, in order to cover the entire speed range.

The advantage of this method compared to the dynamometer method is the greater accuracy of measurements, since only the distance traveled and time are determined, and not the constantly changing force in the automatic coupling.

The disadvantages of this method related to measurement accuracy are listed below:

- When determining the resistance to movement of cars in a train with a locomotive, a measurement error is introduced due to the resistance to movement of the locomotive, which is an order of magnitude greater than the resistance to movement of the car. Therefore, it is necessary to first know the resistance forces of the locomotive during the run-down, which is a separate task.

- Errors that arise when extending the results of measuring the resistance of an individual moving car to the resistance to movement in a train due to the formation of frontal and tail components of aerodynamic drag and the absence of air resistance from inter-car gaps typical for a car in a train.

- Double differentiation of the distance traveled leads to an increase in measurement error.

- Marking the passage of pickets and kilometer posts manually introduces an error in the measurement of the distance traveled.

In addition, this method cannot be applied to testing for a separate freight car, due to the impossibility of stopping the car after passing the measuring section due to the lack of connection with the brake line of the locomotive and, accordingly, the possibility of turning on the brake (the run-out length of the car from a speed of 100 km/h can reach 30 -40 km).

The technical result of the claimed invention is to increase the accuracy of measurements when determining the main resistance to movement of freight cars in a train with a concomitant reduction in the cost of testing.

An increase in measurement accuracy is achieved by using a device for determining the main resistance to movement of freight cars, which includes instruments measuring time, distance traveled, speed of movement and contains a brake activation device located on the freight car, which has brake hoses with quick-release connections for connection to the brake lines of the freight car and a laboratory car or locomotive, a solenoid valve for releasing air from the brake line with a radio-controlled relay and a backup time relay, a battery and a navigation receiver for measuring time, distance traveled and speed, connected to a computer that calculates the main resistance to movement

The test car is uncoupled from the train at a given speed with a delay in braking the test car, which makes it possible to eliminate the influence of the movement resistance of the locomotive and the laboratory car, and also to take into account the values characterizing its frontal and tail aerodynamic resistance. To do this, the tested car is equipped with a brake activation device and is uncoupled from the train at a given speed on a pre-selected straight section of track with a known slope, and from the measured time, change in speed and coordinates of the position of the tested car, the main resistance to movement of the freight car in single motion is calculated using a computer, using aerodynamic calculations on digital models, the aerodynamic resistance of the tested car is calculated during single movement and movement in a train and, based on the obtained experimental and calculated data, the main resistance to movement of the tested car in a train is determined using the formula:

where W _K is the main resistance to movement of the tested car in the train;

W _K0 is the main resistance to movement of a single tested car, obtained in the experiment by processing measurements of the speed of the car and its position on the track;

W _{aer 0} is the aerodynamic drag of a single tested car, obtained by aerodynamic calculation on a digital model of a single car;

W _{aer n} is the aerodynamic drag of the tested car in the train, obtained by aerodynamic calculation on digital models of the car in the train.

In this case, the main resistance of the tested car W _K0 in single motion is determined by the formula:

where M is the gross mass of the tested car;

g - free fall acceleration;

i=ƒ(x) - path slope;

x is the coordinate of the position of the car on the measuring section,

γ=4J/mr ² - inertia coefficient of rotating wheelsets;

J is the moment of inertia of the wheelset;

m is the mass of the wheelset;

r is the radius of the wheelset;

V is the speed of movement of the tested car;

t - time.

Also, the accuracy of determining the main resistance to movement of freight cars in a train is increased due to the fact that a navigation receiver connected to a computer that calculates the main resistance to movement according to formula (2), attached to the car under test, and the device itself is equipped with a device for remote activation of the car brake, containing brake hoses with quick-release connections for connection to the brake lines of the train and the freight car under test, a battery, a solenoid valve for releasing air from the brake line of the freight car with a radio-controlled relay and a backup time relay.

The use of the proposed device makes it possible to increase the accuracy of measurements by an order of magnitude in comparison with the prototype. For example, for the MNP-M7 navigation receiver, the limit of permissible absolute error in speed is ±0.003 m/s, position along the path is ±3 m, and time is ±100*10 ^-9 sec.

Reducing the cost of testing is achieved due to the fact that testing according to the claimed method makes it possible to reduce the number of wagons tested and their loading and unloading. One carriage is tested, not a train of carriages.

The essence of the proposed device is illustrated by graphic material.

Figure 1 shows a test diagram with a device for determining the main resistance to movement of the car;

Figure 2 shows a car brake activation device;

Figure 3 shows a diagram for measuring the resistance to movement of a single car;

Figure 4 shows an example of a digital model of a single test car;

Figure 5 shows an example of a digital model of a tested car in a train;

Figure 6 shows an example of an aerodynamic calculation of a digital model of the car under test.

The method for determining the main resistance to movement of rolling stock is that the test car 1 (Fig. 1) is uncoupled from the laboratory car 2 or from the locomotive 3 and contains a navigation receiver 4 connected to a computer 5 connected to a brake activation device 6, on a given speed on a pre-selected straight section of track 7 with known slopes, rolls down under the influence of kinetic energy accumulated during acceleration, and using the brake activation device 6, delays the activation of the brake of the tested car 1, while the locomotive 3 or the laboratory car 2 is removed to a fixed distance from the tested car 1 in such a way that the tested car 1 is affected by the forces of frontal and tail aerodynamic resistance that arise naturally, and from the recorded change in speed and coordinates of the position of the tested car 1 using a computer 5, the amount of resistance to movement of a single tested car is determined, and using aerodynamic calculation on digital models determines the aerodynamic resistance of the tested car 1 in the train, while the value of the main resistance to the movement of the car in the train is determined by formula (1).

The device, illustrated by figures 2, 3, is placed on the test car 1 (Fig. 1) and consists of a navigation receiver 4 connected via a wire connection to a computer 5, connected via a wire connection to the brake activation device 6, located on a pre-selected straight section path 7. The diagram of the brake activation device 6 is shown in Figure 2. On the laboratory car 2 (Fig. 1) there is a wireless remote control (not shown in the figure) for transmitting a signal remotely to the coil 12 (Fig. 2) of a radio-controlled relay contained in the device 6 brake activation. The brake activation device 6 contains a mechanical key switch 8 states of the electrical circuit connected in series, a battery 9, to which a measuring circuit 10 is connected in parallel, illustrated by figure 3, connected in parallel to them and in series with each other, an additional resistance resistor 11, a radio-controlled relay coil 12, a coil 13 backup time relays connected in parallel to them and in series with each other, an additional resistance resistor 14, an air release electromagnetic valve 15, a radio-controlled relay contact 16 and a time relay contact 17 connected in parallel to power the electromagnetic valve 15, which communicates with the brake system of the tested car 1 through the brake sleeve 18 connected through a quick-release connection 19 with a brake hose 20 connected through an end valve 21 to the brake line 22 of the test car 1 and communicating with the brake system of the laboratory car 2 through a brake hose 23 connected through a quick-release connection 24 with a brake hose 25 connected through the end valve 26 with the brake line 27 of the laboratory car 2. Connected in parallel to the battery 9, the measuring circuit 10 contains a navigation receiver 4 containing a block for generating precise time signals 28 (Fig. 3), a movement speed measurement unit 29, a unit for determining the geographic coordinates of the location of the receiver 30, connected to a computer 5, containing a power supply 31 with connectors for connecting an external power source and an information output unit 32.

Determination of the main resistance of a car in a train is carried out using the following algorithm:

1. The aerodynamic drag of a single test car 1 is calculated using a digital model of the test car 1. An example of such a model is shown in Figure 4. An example of an aerodynamic calculation is shown in Figure b.

2. The aerodynamic resistance of the tested car 1 in the train W _{aer n} is calculated using a digital model of the train. An example of such a digital model is shown in Figure 5.

3. The main resistance to movement of a single test car 1 W _K0 is determined experimentally by processing the results of measuring the speed V, time and coordinates of the position of the test car 1 on a straight section with known slopes when testing according to the claimed method using a computer according to expression (2). The testing scheme is shown in Figure 1.

4. If necessary, the mechanical resistance of a single tested car 1 during rolling W _{fur 0} is determined, for additional comparison of cars by components of movement resistance:

W _{fur 0} =W _K0 -W _{aer 0} ,

where W _K0 is the main resistance to movement of a single tested car 1;

W _{aer 0} is the aerodynamic drag of a single tested car 1.

5. The main resistance of the car to the movement of the tested car in the train W _K is determined, taking into account the fact that the mechanical resistance of a single car W _{mex 0} and the mechanical resistance of the car in the train W _{mex n} are equal:

W _{fur 0} =W _{fur n} ,

W _K =W _{fur 0} +W _{air n} ,

or

where W _{aer n} is the aerodynamic drag of the tested car 1 in the train.

b. The main resistance of the tested car 1 W _K0 in single motion is determined by the formula:

where M is the mass of the tested car 1 gross;

g - free fall acceleration;

i=ƒ(x) - path slope;

x is the coordinate of the position of the tested car 1 on the measuring section,

γ=4J/mr ² - inertia coefficient of rotating wheelsets;

J is the moment of inertia of the wheelset;

m is the mass of the wheelset;

r is the radius of the wheelset;

V is the speed of movement of the tested car 1;

t - time.

The tests are carried out as follows.

In the parking lot, the power of the navigation receiver 4 (Fig. 1) and the computer 5 is turned on, the brake line 22 (Fig. 2) of the tested car 1, connected through the end valve 21 to the brake hose 20 through a quick-release connection 19, is connected to the brake hose 18, which is connected to an air release electromagnetic valve 15, which in turn is connected to the brake hose 23, connected through a quick-release connection 24 to the brake hose 25, connected through the end valve 26 to the brake line 27 of the laboratory car 2 and the brake system of the train (not shown in the figure), the mechanical key switch 8 is open. The brake line 22 of the tested car 1 is charged with compressed air. After charging the brake line 22, the mechanical key 8 is closed, the coils of the radio-controlled relay 12 and the backup time relay 13 receive power from the battery 9, using a signal from the remote control, a signal is sent to the coil of the radio-controlled relay 12, which closes the contact of the radio-controlled relay 16 and the contact of the time relay 17 The air release electromagnetic valve 15 receives power from the battery 9 and closes the communication of the brake hoses 18, 23, thereby disconnecting the brake line 22 of the test car 1 and the brake line 27 of the laboratory car 2, the end valve 26 of the laboratory car is closed, the brake hose 25 the brake line 27 is disconnected from the brake hose 23 using a quick-release connection 24. The brake line 22 is charged, disconnected from the brake line 27, the brake systems are mechanically disconnected, the test car 1 is ready for testing. The locomotive 3 accelerates together with the train, including the laboratory car 2 and the test car 1, to a given speed; at the boundary of the measuring section, the operator (not shown in the figures) located in the laboratory car 2 performs an operation to uncouple the laboratory car 2 and the test car 1, which begins slow motion under the influence of accumulated kinetic energy during acceleration, inertia forces and motion resistance forces. The locomotive 3 moves away from the tested car 1 at such a distance that the air disturbance caused by the train does not affect the air flow flowing into the tested car 1. In this case, the coordinates of the position, speed of the tested car 1 and time are continuously recorded by the navigation receiver 4, connected with the computer 5, representing a measuring circuit 10, connected by the power supply 31 (Fig. 3) of the computer 5 to the battery 9 (Fig. 2), the brake activation device 6 (Fig. 1). In the navigation receiver 4, in the exact time signal generation block 28, exact time signals are generated, at the same time, the motion speed measuring block 29 measures the speed of the car, and the block for determining the geographical coordinates of the location of the receiver 30 determines the coordinates of the position of the car on the railway track. These data are transmitted to the computer 5, mounted on the test car 1, which calculates the value of the movement resistance according to formula (2) and sends it to the information output unit 32.

If the measuring section has been passed or further movement is impractical, the tested car 1 is stopped by turning on the brake using the brake activation device 6. Depending on the version of the brake activation device 5, tests are carried out as follows.

The operator, located in the laboratory car 2, remotely uses a remote control (not shown in the figure) to send a radio signal to the coil of the radio-controlled relay 12, thereby opening the contacts of the radio-controlled relay 16 and the time relay 17, thus the air release solenoid valve 15 loses power. from the battery 9 and goes into the open state, the air from the brake line 22 exits through the connected end valve 21, the brake hose 20, connected through the quick-release connection 19 to the brake hose 18, connected to the hole of the air release solenoid valve 15 and, in response to the pressure drop , the automatic brake is activated and the tested car 1 stops. After stopping the tested car 1, data on movement resistance is removed from the information output unit 32 of the computer 5.

To ensure test safety, a certain time value is fixed on the backup time relay 13, after which the coil of the backup time relay 13 opens its contact 17, and with it the contact of the radio-controlled relay 16, thus the air release solenoid valve 15 loses power from the battery 9 and goes into an open state, the air from the brake line 22 exits through the connected end valve 21, the brake hose 20, connected through a quick-release connection 19 to the brake hose 18, connected to the hole of the air release solenoid valve 15 and, in response to the pressure drop, the automatic brake is activated , and the tested car 1 stops. After stopping the tested car 1, data on movement resistance is removed from the information output unit 32 of the computer 5.

Locomotive 3 approaches the test car 1, the test car 1 is coupled with the laboratory car 2, and the test is repeated.

In this way, a technical result is achieved, which consists in increasing the accuracy of measurements when using a device to determine the main resistance to movement of cars in a train with a concomitant reduction in the cost of testing.

Claims (1)

A device for determining the main resistance to movement of a freight car, including instruments that measure time, distance traveled, and speed, characterized in that it contains a brake activation device located on the freight car, having brake hoses with quick-release connections for connection to the brake lines of the freight car and wagon - laboratory or locomotive, a solenoid valve for releasing air from the brake line with a radio-controlled relay and a backup time relay, a battery and a navigation receiver for measuring time, distance traveled and speed, connected to a computer that calculates the main resistance to movement of a freight car.