FILL LEVEL MONITORING

[0001]The invention relates to a method and an assembly for monitoring the fill level of a sandbox of a sanding system of a rail vehicle.

[0002]It is known in the case of a rail vehicle to undertake sanding via a sanding system in order to improve wheel/rail traction. When required, for example when the rail vehicle is braking or moving off, small amounts of sand are introduced by the sanding system into a wheel/rail gap in front of a wheel of the rail vehicle. A wheel/rail friction value is increased as a result such that the rail vehicle can transmit a higher propulsive or braking force to the rail.

[0003]The sanding system is an operationally important device. If it is faulty or non-functional, in certain situations, for example in the case of an icy rail or a hill start, the journey of the rail vehicle can consequently be interrupted.

[0004]The sanding system is also a device with a safety role because it significantly reduces a required braking distance in emergency situations, for example when braking heavily.

[0005]The sanding system therefore has to have a high degree of availability and functional reliability, which is ensured by regular maintenance and checking of the sanding system on the rail vehicle.

[0006]During maintenance, the sanding system is filled with sand, wherein operating staff check a sand fill level in the sandbox through a viewing window there.

[0007]At the beginning of a journey, the functioning of the sanding system is checked with the aid of operating staff. A judgement is also made as to whether an amount of sand shown in the viewing window is sufficient for an imminent use of the rail vehicle. The sandbox of the sanding system is filled where appropriate.

[0008]This procedure is dependent on the care taken by the operating staff and thus prone to error.

[0009]Because rail vehicles are often used spontaneously and with no long-term planning, it is in practice difficult for the operating staff to judge whether the existing amount of sand is sufficient for performing the spontaneous uses. Sand is therefore often refilled as a precaution, even if is not yet necessary.

[0010]The document DE discloses a sand scattering system for rail vehicles in which a sand controller system stores and processes one or more input signals which serve to start the scattering of sand in rail vehicles in order to improve the functioning and operation of the sand scattering systems.

[0011]The object of the present invention is therefore to provide an improved method and a suitable assembly for monitoring the fill level of a sandbox of a rail vehicle sanding system.

[0012]This object is achieved by the features of claims 1 and 4. Advantageous further developments are provided in the dependent claims.

[0013]The invention relates to a method and to an assembly for monitoring the fill level of a sandbox of a sanding system of a rail vehicle.

[0014]The sanding system is arranged in a rail vehicle and has a sandbox, a sand-conveying system, and a pipeline. The sandbox is connected to the pipeline via the sand-conveying system.

[0015]The sand-conveying system can be activated by a compressed-air pulse in such a way that an already known amount of sand is removed from the sandbox per compressed-air pulse and passes into a wheel/rail gap of the rail vehicle in the form of a sand/compressed air mixture via the pipeline.

[0020]In a preferred further development, the process control system is connected to a controller of the rail vehicle which forms the compressed-air pulses for the sand-conveying system based on a request.

[0024]According to the invention, the process control system is connected to a stationary process control station in order to display the current sand fill level there.

[0025]Automatic and autonomous monitoring of the fill level of a sandbox of a sanding system of a rail vehicle is achieved by virtue of the present invention.

[0026]The present invention can be implemented simply.

[0027]The present invention can be retrofitted in existing vehicles with little effort and low costs.

[0028]The present invention can also be applied or performed in the case of an autonomously operated rail vehicle with no driver.

[0029]By virtue of the present invention, maintenance costs are lessened and previously required laborious visual checks on the rail vehicle are reduced or avoided.

[0030]A set-up time for the rail vehicle is lessened by virtue of the present invention.

[0031]The present invention makes landside monitoring possible which can be performed on the rail vehicles with no additional hardware costs.

[0032]The present invention also makes it possible to identify faults at sanding systems by inference from a reduced or increased application of sand during operation.

[0033]The present invention makes it possible to dispense with previously required viewing windows at the sandbox. Cost-effective manufacturing and design of the sandbox are thus achieved.

[0034]The present invention makes it possible to document identified faults at the sanding system, the documenting preferably being performed with the aid of data communicated from the rail vehicle to a stationary control station, referred to as the landside.

[0035]It is thus made possible to inform maintenance depots during ongoing operation about the fill level of a sandbox of an assigned rail vehicle. Maintenance work can thus be planned better and more effectively.

[0036]The present invention makes it possible to predict and display an empty state of a sandbox. Costs during operation and maintenance of the rail vehicle are reduced as a result.

[0037]The invention will be explained in detail below with the aid of drawings, in which:

[0038]FIG. 1 shows an exemplary embodiment of the invention,

[0039]FIG. 2 shows, with reference to FIG. 1, a characteristic curve of activation of a valve, and

[0040]FIG. 3 shows, with reference to FIG. 1 and FIG. 2, an associated flow chart.

[0041]FIG. 1 shows an exemplary implementation of monitoring according to the invention of the fill level of a sandbox of a sanding system of a rail vehicle. For a first driving direction FR1 of the rail vehicle SFZ, sand SA is conveyed from a first sandbox SB1 by means of compressed air via a first sand-conveying system SFS1 and passes as a sand/compressed air mixture SA via a pipeline into a wheel/rail gap RSSP in front of wheels of a driven first axle A1.

[0042]For a second driving direction FR2 of the rail vehicle SFZ, sand SA is conveyed from a second sandbox SB2 by means of compressed air via a second sand-conveying system SFS2 and passes as a sand/compressed air mixture SA via a pipeline RL into a wheel/rail gap RSSP in front of wheels of a driven second axle A2.

[0043]The compressed air is, for example, blown into an outlet region of the sandbox SB1, SB2 or into the respective sand-conveying system SFS1, SFS2 and mixes there with a defined amount of sand.

[0044]The compressed air required to convey the sand SA and to dispense the sand into the wheel/rail gap RSSP is provided with the aid of a compressed-air supply DVS.

[0045]The compressed-air supply DVS is connected to both sandboxes SB1, SB2 via a shut-off valve AB1 and via respective compressed-air lines. The shut-off valve AB1 ensures that the sanding system can be manually disconnected from the compressed-air system in the event of leaks or faults.

[0046]Sanding via the first sandbox SB1 or via the second sandbox SB2 is selected with the aid of electropneumatic valves EP1, EP2 which ensure the selective supply of compressed air to one of the two sandboxes SB1, SB2 or to one of the two sand-conveying systems SFS1, SFS2.

[0047]To do this, a first valve EP1 is connected between the compressed-air supply DVS and the first sand-conveying system SFS1, whilst a second valve EP2 is connected between the compressed-air supply DVS and the second sand-conveying system SFS2.

[0048]If, for the first driving direction FR1, the sanding is made via the first sandbox SB1, the first valve EP1 is opened and the second valve EP2 is closed. As a result, compressed air passes from the compressed-air supply DVS to the first sand-conveying system SFS1.

[0049]If, for the second driving direction FR2, the sanding is made via the second sandbox SB2, the second valve EP2 is opened and the first valve EP1 is closed. As a result, compressed air passes from the compressed-air supply DVS to the second sand-conveying system SFS2.

[0050]The two valves EP1, EP2 are activated via signals STSIG of a controller ST depending on the driving direction FR1, FR2.

[0051]The sand is discharged with the aid of signal pulses of the signals STSIG which are generated via the controller ST.

[0052]Vehicle parameters FPAR, for example a vehicle speed v and the desired driving direction FR1, FR2, are fed to the controller ST in order to control the amount of sand discharged.

[0053]A discharge of sand triggered by the controller ST is prompted via a sanding request ANF which acts on the controller ST.

[0054]The sanding request ANF is triggered manually by a driver of the vehicle, automatically by a drive/braking system of the rail vehicle, or by other systems of the rail vehicle.

[0055]The controller ST generates the control commands STSIG for the two valves EP1, EP2 on the basis of the request ANF, the vehicle speed v, and the driving direction FR1, FR2.

[0056]The controller ST can here be integrated completely or partially into the process control system LT of the vehicle.

[0057]The control commands STSIG are configured in the form of pulses and as modifiable. On the basis of the depicted system configuration, a corresponding amount of sand is removed from the sandboxes SB1, SB2 by the control commands STSIG and is introduced into the wheel/rail gap RSSP at predetermined time intervals in a predetermined amount.

[0058]The amount of the sand dispensed can be fixed by the pulse-shaped modifiable control commands STSIG. This will be described below in detail on the basis of FIG. 2.

[0059]The controller ST is connected to a process control system LT of the rail vehicle SFZ which is provided or used to control the rail vehicle SFZ.

[0060]A last filling procedure of the sandboxes SB1, SB2 is saved (for example in the form of a piece of data) in the process control system LT.

[0061]With the aid of the process control system LT, as described below a sand consumption is calculated and a prediction made about a remaining operating time or a remaining range of the rail vehicle with regard to a fill level of the sandboxes SB1, SB2 of the sanding system.

[0062]The process control system LT is connected to an operating unit BE of the rail vehicle SFZ.

[0066]The inputting of the last filling procedure, which is used by the process control system LT, is also made possible with the aid of the operating unit BE.

[0067]The process control system LT is connected to a stationary control station or process control station LS, referred to as the landside.

[0068]A sand fill level of a predetermined rail vehicle, or sand fill levels for rail vehicles of a fleet, is or are collected, documented, and possibly displayed there.

[0069]This makes it possible to refill the sand as part of maintenance on the landside in a coordinated fashion or to plan journeys depending on current sand fill levels in an optimized fashion.

[0070]Correspondingly, information for refilling sand is input via the process control station LS and is then transmitted to an associated rail vehicle.

[0071]FIG. 2 shows, with reference to FIG. 1, activation of one of the two valves EP1, EP2, whilst FIG. 3 shows, with reference to FIG. 1 and FIG. 2, details of the invention in a flow chart.

[0072]The activation shows, plotted against time t, a control signal STSIG of the valve with a plurality of pulses 1 to n.

[0073]The pulses 1 to n have a duration t_p and describe together a sanding procedure of the duration t_s.

[0074]The pulses have two states, “on” and “off”. During the “on” state, the conveying and dispensing of sand, assisted by compressed air, take place, whereas these stop in the “off” state.

[0075]A defined amount m of sand is dispensed per pulse. It is ensured by the construction of the sanding system that the amount m dispensed is proportional to the duration of the pulses.

[0076]Two successive pulses have a defined time interval of duration t_i.

[0077]The ratio between the durations t_p and t_i can be set such that an amount m of sand dispensed per unit time can be influenced and known in advance.

[0078]In a first step S1, a calculation of a consumed or dispensed amount of sand M_EP is performed with the aid of the process control system LT.

[0083]Thus, for the amount of sand M_EP, which has been consumed since the associated sandbox SBv was last filled at a valve EPv (where v=1,2, etc, i.e. v designates a number of valves at the sandbox in question):

$M_{\mathrm{EPv}}=\sum _{k=1}^{n_{\mathrm{qes}}}\left(\frac{t_p}{t_i}*m*t_{\mathrm{sk}}\right)$

[0086]If precisely one valve EPv is installed at each sandbox SBv, the amount of sand M_EPv is equal to the consumption of the sandbox SBv.

[0087]This is assumed for the method described here.

[0088]If this is not the case on a rail vehicle in question and a plurality of valves are associated with a sandbox there, the number of the respective valves must correspondingly be taken into account for the calculation.

[0089]The total amount M_ges of sand consumed per rail vehicle can then be found from the sum of the amounts of sand over all

[0091]In a second step S2, calculation of a remaining amount of sand is performed.

[0092]The remaining amounts R_EPV of sand per sandbox SBv are calculated by the process control system LT from the calculated consumptions M_EPv and M_ges, and a total remaining amount R_ges of the vehicle is determined.

[0093]For this purpose, the process control system LT has stored the maximum filling amounts or the maximum fill levels per sandbox SBv.

[0094]The remaining amounts R_EPv and R_ges are calculated from the differences in the maximum filling amounts per tank M_max and the calculated consumptions M_EP, or the associated fill levels are calculated.

[0095]In a third step S3, a prediction of a remaining operating distance is determined or calculated.

[0096]On the basis of the calculated fill levels of the sandboxes and an already known average consumption d per kilometer traveled since the last time the sandboxes were filled, a prediction is calculated of for how many kilometers there is still enough sand.

[0097]This is calculated per sandbox SBv or per sand valve EPv as follows:

[0098]First, the average consumption per valve is calculated as follows:

[0100]If the average consumption w_zur falls below a settable mini-mum value, for example 100 km, the calculation of d_EPV is not performed. In this case, a settable standard value is assumed, for example an average value before the last refill.

[0101]A predicted remaining distance S_RestEPv of the respective sandbox SBv at the valve EPv is calculated as follows:

$s_{\mathrm{RestEPv}}=\frac{R_{\mathrm{EPv}}}{d_{\mathrm{EPv}}}$

[0102]In order to take into account different types of usage of the vehicle (during, for example, a change in the driving direction and the associated switchover of the sanding system), in addition to the remaining distances S_RestEP of the individual sandboxes SB, a remaining distance for the average consumption of the whole vehicle is calculated:

$s_{\mathrm{RestGes}}=\frac{R_{\mathrm{ges}}}{d_{\mathrm{ges}}}$$\mathrm{where}{d}_{\mathrm{ges}}=\frac{M_{\mathrm{ges}}}{w_{\mathrm{zur}}}$

(calculated analogously to d_EPv)

[0103]In a fourth step S4, generation and communication of a warning are performed.

[0104]If the remaining amounts R_EPv, R_ges or the remaining distances S_RestEPv, S_RestGes fall below settable threshold values, the process control system LT generates a warning and sends it via a radio link to the process control station LS where it can be accessed by maintenance staff.

[0105]Additionally or optionally, the warning is displayed at the operating unit BE of the rail vehicle.

[0106]In a fifth step S5, display and communication of the calculated values are performed.

[0107]The amounts of the sand consumed M_EPv and M_ges and the remaining amounts R_EPV and R_ges are communicated as values from the process control system LT via a suitable remote connection to the process control station LS which stores this data for all the rail vehicles and allows it to be used by the maintenance staff.

[0108]Additionally or optionally, the values are displayed via the operating unit BE of the rail vehicle.

[0109]In a sixth step S6, weather forecasts and route topologies are taken into account. The amount of sand consumed is generally dependent on the weather and the topology of the route traveled. The process control station LS therefore optionally uses further data for improving the accuracy of the values.

[0110]In order to calculate improved remaining operating distances and improved remaining amounts of sand, the process control station LS automatically takes into account available weather forecasts for the route to be traveled. In the case of poor weather conditions, a higher consumption of sand is to be expected, which is taken into account in the calculation by a suitably chosen factor.

[0111]The route topology of the route to be traveled is likewise taken into account via a suitably chosen factor. The calculation of the improved remaining distance S_VerbRestEPv per valve is then made by:

$s_{\mathrm{VerbRestEPv}}=s_{\mathrm{RestEPv}}*{\lambda }_{\mathrm{Wetter}}\star {\lambda }_{\mathrm{Strecke}}$

where λ_Wetter is a factor which is dependent on the weather forecast for the planned route, and λ_Strecke is a factor which depends on the route topology.

[0112]The improved value for S_RestGes is calculated analogously.

[0113]The values thus improved for the remaining operating distances are stored in the process control station LS and made available to the maintenance staff.

[0114]The warning described in step S4 is calculated process control station LS based on the improved values. Additionally or optionally, the improved remaining operating distance or remaining amounts of sand thus calculated are made available to the vehicle via the remote connection for display at the operating unit BE.

[0115]In a seventh step S7, data is input relating to a sand refill which has been undertaken.

[0116]When the sandboxes are refilled, the maintenance staff input this data via the operating unit BE at the vehicle for the process control system LT.

[0117]Alternatively or additionally, this data is input and stored on the landside. It is then made available by the landside process control station LS to the vehicle via the remote connection.

[0118]When the process control system LT and the process control station LS receive this data, they correspondingly reset all the calculated values and restart with the calculations according to the steps S3, S4, and S6.

[0119]The data relating to the filling procedure can here be input either per sandbox or across the board for the whole vehicle.

[0120]Alternatively or additionally, a check is made when the sandboxes are refilled as to whether the remaining amounts of sand in the tanks SBv correspond to the projected amounts R_EPV to a plausible extent.

[0121]If there is a significant deviation between the individual sandboxes, it can be inferred that there is a fault in the sanding system.