Technical field

The present invention is generally in the field of braking systems for at least one vehicle; in particular, the invention relates to a “snow-brake” control system, a braking system, and a vehicle.

Prior art

In the vehicle sector, “snow-brake” braking refers to the application of braking with limited force and duration. This braking is applied for the purpose of preventing the formation of ice and/or snow deposits on a braking means of the vehicle, for example on the braking application means of the braking means.

In one example, the braking means may be a pneumatic, or electropneumatic, or mechanical, or electromechanical brake, etc. The braking application means of the braking means may, for example, be a brake shoe suitable for applying a braking force to the wheel, or a pad suitable for applying a braking force to a braking organ, for example, a disc, associated with a wheel of the vehicle or associated with an axle associated with at least one wheel.

Figure 1 shows an exemplifying situation wherein snow and/or ice 100 has accumulated on a brake shoe 102 of a braking means 104.

Snow and ice 100, under certain environmental conditions, may accumulate on the braking means, for example, on the braking application means 102 (for example, on the brake shoe or on the pad and/or disc, on the caliper). In some rarer cases, snow and/or ice 100 may also accumulate on the wheel 106 or the axle whereto the wheel 106 is coupled.

In the following, special reference will be made to the railway vehicle sector. What is being described may, however, also apply to vehicles in other fields. When the vehicle is a vehicle in the railway sector, with regard to the definition of the safety integrity level SIL, reference may be made to European standards EN50129, EN50159, EN 50126-1, EN 50126-2, EN 50128, according to the latest update available on the filing date of the present invention, where:

- EN50126 [“Railway applications. The specification and demonstration of reliability, availability, maintainability and safety (RAMS)].

- EN50128 [“Railway applications. Communications, signaling and processing systems. Software for railway control and protection systems”]

- EN50129 [“Railway applications. Communication, signaling and processing systems. Safety related electronic systems for signaling”].

- EN50159 [“Railway applications. Communication, signaling and processing systems. Safety-related communication in transmission systems”].

In particular, the EN50126 standard defines the methodologies for assigning the SILO/1/2/3/4 safety levels (with safety integrity level SIL4 indicating the maximum safety integrity level) to the subsystems making up the system in question, based on the results of the Safety Analysis, and the standards EN50128 and EN50129 define the design criteria to be applied to the software and hardware components, respectively, based on the SIL levels assigned based on said Safety Analysis results.

A control means, a device, a unit or module, etc., may be considered implemented according to a high safety integrity level when made at least according to a SIL >= 3 safety integrity level.

As may be observed in Figure 2, in the prior art, “snow-brake” braking is managed by a control means 200 that is also arranged to manage and control the service braking. Such control means 200 is implemented according to a low safety integrity level (SIL < 2).

The fact that “snow-brake” braking is managed at a low safety integrity level exposes “snowbrake” braking to a higher probability of malfunction and the risk that such a malfunction will go undetected. Failure to apply “snow-brake” braking, due, for example, to a malfunction of the control means 200 or the braking means 204 or the braking application means 202 thereof, may result in an undue accumulation of snow or ice on the braking means 204, such as on the braking application means 202, or on the wheel 206 or on the axle associated with the wheel 206. In this case, should it be necessary to apply emergency braking, due to the unexpected presence of snow or ice, the emergency braking may be initially applied in a degraded manner. Only when the snow or ice has been cleared may the expected emergency braking be effectively applied. As a result, the application of degraded emergency braking may negatively impact the performance of said emergency braking, resulting in the lengthening of the equivalent stopping time of the vehicle, despite the fact that the emergency braking is managed according to a high safety integrity level (SIL4).

Summary of the invention

One object of the present invention is therefore to provide a solution that improves the safety level with which “snow-brake” braking is managed, without impacting the development costs of the systems responsible for managing the service braking and emergency braking.

The aforesaid and other objects and advantages are achieved, according to one aspect of the invention, by a “snow-brake” braking control system having the features defined in claim 1, according to a further aspect of the invention, by a braking system having the features defined in claim 13, and, according to yet another aspect of the invention, by a vehicle having the features defined in claim 14. Preferred embodiments of the invention are defined in the dependent claims, the content of which is to be understood as an integral part of the present description.

Brief description of the drawings

The functional and structural features of some preferred embodiments of a “snow-brake” control system, of a braking system, and of a vehicle according to the invention will now be described. Reference is made to the accompanying drawings, wherein:

- Figure 1 shows an exemplifying situation wherein snow and/or ice has accumulated on the braking application means;

- Figure 2 shows a “snow-brake” braking control system according to the prior art; - Figure 3 shows an embodiment of a control system of the “snow-brake” according to the invention; and

- Figure 4 shows a further embodiment of a control system of the “snow-brake” according to the invention.

Detailed description

Before explaining in detail a plurality of embodiments of the invention, it should be clarified that the invention is not limited in its application to the design details and configuration of the components presented in the following description or illustrated in the drawings. The invention may assume other embodiments and be implemented or constructed in practice in different ways. It should also be understood that the phraseology and terminology have a descriptive purpose and should not be construed as limiting. The use of “include” and “comprise” and the variations thereof are intended to cover the elements set out below and the equivalents thereof, as well as additional elements and the equivalents thereof.

Referring initially to Figure 3 and Figure 4, an embodiment of a “snow-brake” control system 300, 400 of at least one vehicle, particularly of at least one railway vehicle, is described in the following.

“Snow-brake” braking is braking that, when applied, is suitable for removing any accumulated ice and/or snow on a braking means 304, such as on a braking application means 302 of the braking means 304, and/or on a wheel 306 of the at least one vehicle, and/or on a braking organ associated with a wheel of the at least one vehicle or associated with an axle whereto at least one wheel of the vehicle is coupled. When ice or snow accumulates, it will impair the proper application of the braking force by the braking means 304.

In other words, “snow-brake” braking is a braking that is suitable for preventing the formation of ice and/or the depositing of snow on a braking means 304, such as on a braking application means 302 of the braking means 304, and/or on a wheel 306 of the at least one vehicle, and/or on a braking organ associated with a wheel of the at least one vehicle or associated with an axle whereto at least one wheel of the vehicle is coupled. For example, the braking organ may be a brake disc. For example, the braking application means 302 of the braking means 304 may be a brake shoe when it is designed to act directly upon the wheel, or it may be a brake pad when it is designed to act upon the brake disc. Additional types of braking organs and braking application means are however applicable to the present invention.

During the application of the “snow-brake” braking force, due to the effect of overheating and/or friction generated by the contact between the braking means 304 and the wheel 306 and/or the braking organ associated with a wheel of the at least one vehicle or associated with an axle whereto at least one wheel of the vehicle is coupled, the snow and ice are removed or melted. For example, the contact between the braking means 304 and the wheel 306 and/or the braking organ associated with a wheel of the at least one vehicle or associated with an axle whereto at least one wheel of the vehicle is coupled, may occur by means of a movement of the braking application means 302 of the braking means 304.

The control system comprises a first control means 301 arranged to:

- receive a signal that is indicative of a request to perform said “snow-brake” braking 305;

- generate a “snow-brake” braking application command 308 when it receives the signal that is indicative of a request to perform said “snow-brake” braking 305.

The signal indicative of a request to perform said “snow-brake” braking 305 is a signal that is indicative of the fact that it is necessary to apply “snow-brake” braking. The “snow-brake” braking application command 308 is a signal which is generated in response to the receipt of the signal that is indicative of a request to perform said “snow-brake” braking 305 and that is generated for the purpose of requesting the application of “snow-brake” braking to said wheel 306 and/or to the braking organ associated with a wheel of the at least one vehicle or associated with an axle whereto at least one wheel of the vehicle is coupled. Therefore, the “snow-brake” braking application command 308 may be a signal to indicate that the braking means 304 must be operated in order to apply “snow-brake” braking. In one example, the signal that is indicative of a request to perform said “snow-brake” braking 305 and/or the “snow-brake” braking application command 308 may be electrical signals.

For example, the first control means 301 may be, or comprise, at least one processor, one microprocessor, one controller, one microcontroller, one FPGA, or one PLC, etc.

The control system 300, 400 comprises a second control means 303 arranged to:

- receive said “snow-brake” braking application command 308 from the first control means 301;

- request that a braking means 304 of the vehicle apply said “snow-brake” braking to said wheel 306 or to the braking organ associated with a wheel of the at least one vehicle or associated with an axle whereto at least one wheel of the vehicle is coupled when the second control means receives said “snow-brake” braking application command 308.

In order to request that the braking means 304 of the vehicle apply “snow-brake” braking, the second control means 303, in response to receiving the “snow-brake” braking application command 308, may issue an actuation signal 307. Depending upon the type of braking means 304 (for example pneumatic, electropneumatic, electromechanical), the actuation signal may be a pneumatic signal or an electric actuation signal, etc.

For example, the actuation signal may be a pneumatic signal suitable for supplying a pneumatic braking cylinder of the braking means 304 with brake fluid at a given pressure. Or, for example, the actuation signal 307 may be an electrical signal suitable for controlling the opening and closing of an electropneumatic valve that is suitable for regulating the pressure of a brake fluid to be supplied to a pneumatic braking cylinder of the braking means 304.

The second control means 303 may, for example, be, or comprise, at least one processor, one microprocessor, one controller, one microcontroller, one FPGA, or one PLC, etc.

The first control means 301 is further designed to: - receive an actual braking signal 310 that is indicative of actual braking that is effectively applied by the braking means 304 to the wheel 306, or to the braking organ associated with the vehicle wheel or associated with the axle coupled to the vehicle wheel, in response to the “snow-brake” braking application command 308 generated by the first control means 301;

- compare the actual braking indicated by the actual braking signal 310 with the requested “snow-brake” braking;

- determine that “snow-brake” braking has not been properly applied when the actual braking indicated by the actual braking signal 310 does not correspond to the requested “snow-brake” braking.

In other words, the first control means 301, through a comparison of the actual braking indicated by the actual braking signal 310 and the requested “snow-brake” braking (i.e., that which is expected when the braking means 304 correctly applies “snow-brake” braking) may verify that “snow-brake” braking has actually been applied. By means of such a comparison, the first control means 301 may immediately determine whether the second control means 303 and/or the braking means 304 and/or the braking application means 302 of the braking means 304 is not functioning properly and is not applying the expected “snow-brake” braking.

Actual braking that is effectively applied by the braking means 304 to the wheel 306 in response to the “snow-brake” braking application command 308, which was generated by the first control means 301 and was transmitted/received to/from the second control means, may be understood to mean the actual braking that was generated as a result of the fact that the application of “snow-brake” braking has been requested by means of the “snow-brake” braking application command 308.

Preferably, the first control means 301, when it is determined that the “snow-brake” braking has not been properly applied, may also be designed to: a) generate a fault signal 312 that is indicative of the fact that the “snow-brake” braking has not been properly applied; and/or b) generate an emergency braking request signal 314 indicative of the necessity to perform emergency braking.

Preferably, the first control means 301 may be implemented according to a first safety integrity level SIL and said second control means may be implemented according to a second safety integrity level SIL. The first safety integrity level SIL may be greater than the second safety integrity level SIL.

Preferably, the first control means 301 may be implemented according to a first safety integrity level SIL4 and the second control means may be implemented according to a second safety integrity level SIL2.

Preferably, as may be observed in Figure 3, the first control means 301 may be distinct from the second control means 303.

Otherwise, as may be observed in Figure 4, the first control means and the second control means may be comprised within one single control unit 402. For example, the control unit 402 may be the control unit responsible for controlling all of the functions in relation to the braking of such a vehicle (for example, service braking, emergency braking, parking braking).

Preferably, the first control means 301 may be arranged to determine that said actual braking, as indicated by the actual braking signal 310, does not correspond with the requested “snowbrake” braking when:

- a first actual braking application intensity value differs from a second requested “snow-brake” braking application intensity value by at least a predetermined braking application intensity difference value; and/or

- a first actual braking application duration differs from a second requested “snowbrake” braking application duration by at least a predetermined braking application duration difference.

In a numerical example, considering a predetermined braking application intensity difference value equal to 50N, if the “snow-brake” braking involves the application of a second braking application intensity value of 200N but the first actual braking application intensity value indicated by the actual braking signal 310 is equal to 100N, the first control means 301 may determine that said actual braking, as indicated by the actual braking signal 310, does not correspond to the requested “snow-brake” braking. If, on the other hand, the “snowbrake” braking involves the application of a second braking application intensity value of 200N but the first actual braking application intensity value indicated by the actual braking signal 310 is equal to 190N, the first control means 301 will be able to determine that said actual braking indicated by the actual braking signal 310 corresponds to the requested “snow-brake” braking.

In a further numerical example, considering a predetermined braking application duration difference of 2 seconds, if the “snow-brake” braking involves the application of a second “snow-brake” braking application duration of 10 seconds but the first actual braking force application duration, as indicated by the actual braking signal 310, is equal to 6 seconds, the first control means 301 may determine that said actual braking, as indicated by the actual braking signal, does not correspond to the requested “snow-brake” braking. If, on the other hand, the “snow-brake” braking involves the application of a second “snow-brake” braking application duration of 10 seconds but the first actual braking application duration, as indicated by the actual braking signal 310, is equal to 9 seconds, the first control means 301 may determine that said actual braking, as indicated by the actual braking signal 310, corresponds to the requested “snow-brake” braking.

Preferably, the second control means 303 may also be designed to manage the application of the service braking. Service braking, for example in the railway industry, may be understood to mean normal operational braking in order to stop the railway vehicle and in order to reduce speed thereof.

Preferably, the first control means 301 may also be arranged to manage the application of emergency braking. Emergency braking, for example in the railroad industry, may be understood to indicate a breaking force that is significantly greater when compared to standard service braking. Emergency braking may only be used as a last resort in an emergency situation wherein it is necessary to stop the vehicle as soon as possible. For example, emergency braking uses the maximum available braking force. Emergency braking may also be braking that is completely separate from conventional service braking and designed to stop the vehicle as quickly as possible.

Preferably, the first control means 301 may be arranged to receive, via a communication means, the signal that is indicative of a request to perform said “snow-brake” braking 305 from a third control means 316.

The third control means 316 may be included in the vehicle or may be remote in relation to the vehicle (for example, included in a remote traffic control station).

For example, the communication means may be a wired communication means, for example a vehicle CAN line, or a wireless means, such as wireless Bluetooth.

Preferably, the third control means 316 may be designed to forward the signal that is indicative of a request to perform said “snow-brake” braking 305 to the first control means 301 when:

- a driver of the vehicle operates a control means 318; or

- a snow or ice monitoring system 320 determines that there is ice or snow on said braking means 304 or on said vehicle wheel 306 or on said braking organ associated with the vehicle wheel or associated with the axle coupled to the vehicle wheel.

For example, the control means 318 may be a button, switch, lever, or software button shown on a display. The control means 318 may be placed, for example, in a vehicle cabin suitable for accommodating the driver of the vehicle.

For example, the monitoring system 320 may comprise a sensor means, such as an optical sensor that is designed to acquire infrared images or signals, or the like, of the braking application means or of the wheel or axle. The monitoring system 320 may also be combined with an artificial intelligence and/or machine learning algorithm that is suitable for evaluating images acquired by the monitoring system 320 and to determine whether snow or ice is present. The infrared images/information acquired by the monitoring system 320 may be stored, for example, in a database or memory.

Preferably, the third control means 316 may be designed to forward said signal indicative of a request to perform said “snow-brake” braking 305 to the first control means 301 when:

- a temperature sensor means measures a temperature outside the vehicle that is below a predetermined temperature threshold.

For example, the temperature threshold may be equal to 0°C.

For example, the signal that is indicative of a request to apply said “snow-brake” braking 305 and/or the “snow-brake” braking application command 308 may be generated or forwarded continuously over time, or only at predetermined time intervals that are spaced apart by a predetermined time interval.

In a further aspect, the present invention relates to a braking system for a vehicle. In one embodiment, the braking system comprises:

- a braking means 304 that is designed to apply “snow-brake” braking to a wheel 306 of the vehicle or to a braking organ associated with a wheel of the vehicle or associated with an axle coupled to a wheel of the vehicle;

- a control system 300, 400 for the “snow-brake” braking of at least one vehicle according to any one of the embodiments described above.

In a still further aspect, the present invention relates to a vehicle. In one embodiment, the vehicle comprises a braking system according to one of the embodiments described above.

Clearly, the vehicle may comprise one or more of the following: at least one wheel (306), at least one braking organ designed to be associated with a vehicle wheel or an axle coupled to a vehicle wheel.

Preferably, the at least one vehicle may comprise at least one railway vehicle. Otherwise, the vehicles may also be more than one, and they may be associated therebetween in order to form a convoy of vehicles, such as a railway convoy. Preferably, however, the present invention may also be applicable to any type of vehicle. This may include, for example, railway vehicles/convoys, road vehicles, a car, a truck (for example a highway semi-trailer truck, a mining truck, a truck for transporting timber or the like) or similar, and the route may be, for example, a track, a road, or a trail.

Thus, the benefit achieved is to have provided a solution that improves the level of safety with which “snow-brake” braking is managed but without impacting the development costs of those systems that are responsible for managing service braking and emergency braking.

Various aspects and embodiments of a “snow-brake” control system, of a braking system, and of a vehicle according to the invention have been described. It is understood that each embodiment may be combined with any other embodiment. Moreover, the invention is not limited to the embodiments described, but may be varied within the scope defined by the appended claims.