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Title:
ROTATIONAL MONITORING SYSTEM OF AT LEAST ONE AXLE FOR A RAILWAY VEHICLE OR TRAIN
Document Type and Number:
WIPO Patent Application WO/2020/222120
Kind Code:
A1
Abstract:
A rotational monitoring system of at least one axle (WRM) designed to identify at least one axle controlled by it having an estimated instantaneous linear speed lower than a predetermined instantaneous linear limit speed, and remove the braking force to one or more wheels of the axle identified to have an estimated instantaneous linear speed lower than the predetermined instantaneous linear limit speed, by canceling a pressure to brake cylinders associated with the at least one axle identified to have an estimated instantaneous linear speed lower than the predetermined instantaneous linear limit speed. The cancellation of a pressure is obtained by acting on an electro -pneumatic valve (20) designed to perform a Remote Release function associated with the pneumatic circuits generating braking pressure for the brake cylinders and adapted to cancel a residual braking pressure.

Inventors:
TIONE ROBERTO (IT)
Application Number:
PCT/IB2020/053994
Publication Date:
November 05, 2020
Filing Date:
April 28, 2020
Export Citation:
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Assignee:
FAIVELEY TRANSPORT ITALIA SPA (IT)
International Classes:
B60T8/17; B60T8/32; B60T13/26; B60T13/36
Domestic Patent References:
WO2019053599A12019-03-21
WO2017021837A12017-02-09
Attorney, Agent or Firm:
DEAMBROGI, Edgardo et al. (IT)
Download PDF:
Claims:
CLAIMS

1. Rotational monitoring system of at least one axle (WRM) for a railway vehicle or train, the rotation monitoring system of at least one axle (WRM) being arranged for:

- identifying at least one axle controlled by it having an estimated instantaneous linear speed lower than a predetermined instantaneous linear limit speed;

- removing a braking force to one or more wheels of the axle identified to have an estimated instantaneous linear speed lower than said predetermined instantaneous linear limit speed, by canceling a pressure to brake cylinders associated with said at least one axle identified to have an estimated instantaneous linear speed lower than said predetermined instantaneous linear limit speed;

the rotational monitoring system of at least one axle (WRM) being characterized in that the cancellation of a pressure to brake cylinders associated with said at least one axle identified to have an estimated instantaneous linear speed lower than said predetermined instantaneous linear limit speed is obtained by acting on an electro -pneumatic valve (20) arranged to perform a Remote Release function associated with pneumatic circuits generating brake pressure for said brake cylinders and adapted to cancel a residual braking pressure.

2. Rotational monitoring system of at least one axle (WRM) according to claim 1, wherein the electro-pneumatic valve (20) arranged to perform a Remote Release function is conditioned by a hardware timeout circuit (507, 511), or by a software timeout function, arranged to limit an excitation command of a solenoid (503) associated with said electro pneumatic valve (20) for a predetermined continuous time (T).

3. Rotational monitoring system of at least one axle (WRM) according to claim 2, wherein the predetermined continuous time (T) assumes a value equal to or greater than 10 seconds.

4. Rotational monitoring system of at least one axle (WRM) according to claim 2 or 3, wherein the software timeout function is realized directly inside a software of the rotational monitoring system of at least one axle (WRM). 5. Rotational monitoring system of at least one axle (WRM) according to any one of the preceding claims, wherein said predetermined instantaneous linear limit speed is a function of a linear reference speed of the vehicle.

Description:
Rotational monitoring system of at least one axle for a railway vehicle or train

Technical field

The present invention generally relates to the field of railway braking systems; in particular, the invention relates to a rotational monitoring system of at least one axle for a railway vehicle or train.

Background art

In the railway transport system, the instantaneous adhesion value between the wheel and the rail represents the maximum braking force limit currently applicable to the axles without the wheels of said axles starting a progressive slipping phase.

If an axle enters the slipping phase, if the applied braking force is not promptly and suitably reduced, the axle gradually loses angular speed until it reaches complete locking, with consequent immediate overheating and serious damage due to overtemperature of the surface of the wheels of said axle at the point of contact between the wheels and the rail.

It is known that the situation just described, in addition to significantly lengthening the stopping distances due to a further reduction in the friction coefficient, can cause a derailment at high operating speeds of the railway vehicle.

To overcome the drawback described, pneumatic railway braking systems are equipped with a protection system, known as an anti- slip system.

A known anti-slip system is illustrated by way of example in figure 1, in the case of a four- axle railway vehicle 102, 103, 104, 105. A braking system 110 produces the pneumatic braking pressure as a function of a request for braking pressure or braking force, not shown in figure 1, by supplying brake cylinders 111, 112, 113, 114.

Each brake cylinder 111, 112, 113, 114 is in charge of braking a respective axle 102, 103, 104, 105, by means of pneumatic ducts 115, 116. Four anti-slip valve units 117, 118, 119, 120, piloted by the anti- slip device 101, are interposed between the pneumatic supply conduits 115, 116 and the respective brake cylinders 111, 122 and 113, 114.

Angular speed sensors 106, 107, 108, 109 detect the angular speed of the axles 102, 103, 104,

105, respectively. Said angular speed sensors 106, 107, 108, 109 are electrically connected to the anti-slip device 101, continuously supplying an electric signal representing the instantaneous angular speed information of each axle 102, 103, 104, 105.

The anti-slip device 101 continuously estimates the instantaneous linear speed of the vehicle through operations performed on the information of the estimated instantaneous linear speed of the axles 102, 103, 104, 105 derived from the relative measured angular speeds.

Continuously evaluating differences AV between the estimated instantaneous linear speed of the single axle and the estimated instantaneous linear speed of the vehicle, the anti-slip device 101 detects whether one or more axles have started a slipping phase. If one or more axles have started a slipping phase, the anti- slip device controls the slipping of said axles by appropriately reducing and modulating the pressure to the brake cylinders relating to the slipping axles, acting on the valve units relating to said slipping axles by means of known algorithms, for example described in EP3393873, W02017175108, preventing said axles from incurring a blocking state and trying to obtain the best braking force while remaining in the slipping phase.

Said anti-slip valve units 117, 118, 119, 120 may each assume the detailed shape represented by the pair of electro-pneumatic valves 220, 221, illustrated in figure 2.

The electro-pneumatic valves 220, 221 are energized by the anti- slip device 201 by means of respective switching elements 202, 203. Such switching elements 202, 203 are typically solid state electronic components.

For simplicity of illustration, figure 2 does not show the connection of solenoids, i.e. electric coils, 204, 205 to ground. The anti-slip valve units 117, 118, 119, 120 can assume four overall states.

The first state is defined as“filling” and corresponds to a state in which both the electro pneumatic valves are de-energized, as shown in figure 2: the electro -pneumatic valve 220 allows access to the pressure present in a pneumatic conduit 215, corresponding to the pneumatic conduit 115, 116 of figure 1, to a brake cylinder 211, corresponding to the brake cylinder 111, 112, 113, 114 of figure 1, while the electro-pneumatic valve 221 prevents the emptying of the brake cylinder 211 and of the pneumatic conduit 215 to the atmosphere. This state represents the rest, or non-intervention, state of the anti- slip device, as it actually constitutes a direct connection between the brake cylinder 211 and the pneumatic conduit 215, through which the brake system directly controls the pressure to the brake cylinder 211 from a null value to a maximum value.

The second state is defined as“holding” and corresponds to a state in which the electro pneumatic valve 220 is energized. In this case, the pressure in the brake cylinder 211 cannot be changed by pressure variations in the pneumatic conduit 215. The electro -pneumatic valve 221 continues to keep the brake cylinder 211 isolated from the atmosphere. Overall, the pressure to the brake cylinder 211 maintains its value indefinitely unless there are leaks in the brake cylinder.

The third state is defined as“discharge” and corresponds to a state in which both the electro pneumatic valves 220, 221 are energized. In this case, the pressure in the brake cylinder 211 cannot be changed by pressure variations in the pneumatic conduit 215. The energized electro pneumatic valve 221 connects the brake cylinder 211 to the atmosphere, reducing the pressure to the brake cylinder, possibly down to the null value.

The fourth state is defined as“prohibited” and corresponds to a state in which only the electro pneumatic valve 221 is energized. In this case, the electro-pneumatic valve connects both the brake cylinder 211 and the pneumatic conduit 215 directly to the atmosphere, causing an undue discharge to the atmosphere of the pressure produced by the brake system. The anti- slip devices are regulated by European railway regulations:

UIC541-05 “BRAKES - SPECIFICATIONS FOR THE CONSTRUCTION OF VARIOUS BRAKE PARTS - WHEEL SLIDE PROTECTION DEVICE (WSP)”

EN 15595“Railway applications - Braking - Wheel slide protection”

Both standards pay close attention to the case in which the railway train can be operated at speeds above 200Km/h. In particular, EN15595 §4.2.4.3 “Special features of WSP systems for high speeds ( v>200km/h )” and sub-chapters, recommends the use of a WRM“Wheel Rotation Monitoring” device, i.e. for monitoring the rotation of the wheels, in charge of verifying that the estimated linear instantaneous speed of the single axle, derived from its instantaneous angular speed, does not fall below a linear instantaneous limit speed, which is a function of a vehicle reference linear speed, for more than 10 seconds.

Furthermore, in §4.2.4.3.3“Recommended features,” it is recommended that the WRM device be equipped with the functionality of being able to remove the braking force in the event that the estimated linear instantaneous speed of the single axle falls below the reference linear speed of the vehicle, however limiting the removal of the braking force for a period not exceeding 10 seconds.

Furthermore, in §4.2.4.3.2 “Functional characteristics” it is recommended that the electrical/electronic circuits of the WRM device be independent of the electrical/electronic circuits of the anti- slip device.

The §4.2.4.3.3 recommendation implies the possibility that the WRM device may act on an electro-pneumatic valve, referred to as discharge solenoid valve, which causes the discharge of the brake cylinder associated with the axle that has been verified as subjected to the estimated linear speed loss below the reference linear speed of the vehicle.

The §4.2.4.3.2 recommendation prevents the WRM device from acting electrically on one of the solenoids belonging to the anti- slip valve modules, as this would involve sharing portions of the electrical circuit. The prior art provides that the discharge solenoid valve, should it be activated both by the anti-slip device and by the WRM device, is provided with two independent solenoids, in particular a first solenoid assigned to the anti-slip device and a second solenoid assigned to the WRM device.

EP 1577185 describes an integrated system consisting of a WSP anti-slip device and a WRM device, also known as an Anti-lock device. In particular, Figure 2 of EP1577185, shown as figure 3 in the present patent application, illustrates an anti-slip valve with electro-pneumatic pilot valves 12, 13, made redundant by electro-pneumatic pilot valves 14, 15, respectively. The electro-pneumatic pilot valves 12, 13 are controlled by the anti-slip device and the electro pneumatic pilot valves 14, 15 are controlled by the anti-lock device, if a failure of the anti slip device has been identified, or the estimated instantaneous linear speed of the single axle associated with said electro-pneumatic valves 14, 15 falls below the linear reference speed of the vehicle, as recommended in EN15595 §4.2.4.3.

The recent developments of railway braking systems have led to a considerable integration and simplification of the railway braking systems, such that the electro-pneumatic components for controlling the braking pressure and the electro -pneumatic components for controlling the anti-slip function coincide. Examples are patent EP3148853 and patent EP2830918.

In figure 1 of EP3148853, shown as figure 4 in the present patent application, the electro pneumatic valve 10 operates, as described in EP3148853, as a pilot for filling a pilot chamber of the relay valve RV controlled by the braking control unit BCU both in the braking control phase and in the anti-slip phase. Furthermore, the electro-pneumatic valve 12 acts as a pilot for emptying the pilot chamber of the relay valve RV controlled by the braking control unit BCU both during the braking control phase and in the anti-slip phase. Complex interlocking logic controls the software braking control and anti-slip control functions, both of which access the same electro-pneumatic valves to implement the respective functions. Furthermore, it is prior art that in most applications a railway braking system is provided with a function defined as Remote Release. This Remote Release function is necessary to remedy cases of unwanted residual pressure present in the brake cylinders associated with said braking system. Said residual pressure can be maintained at the brake cylinders due to an unexpected failure of one or more components constituting said braking system. A residual pressure, when of high value, can cause the locking of the associated wheels with consequent serious damage to the wheels at the point of contact with the rail. A residual pressure, when of a value not such as to cause the wheels to lock, causes a continuous unwanted braking action due to a dangerous overheating of the braking friction elements, with the risk of starting a fire, particularly serious in underground trains, inside tunnels with no escape route for passengers. The Remote Release function is normally implemented by means of an electro -pneumatic valve inserted inside the braking system in a pneumatic diagram position where, in rest condition, or de-energized, it does not interfere with the normal functions of said braking system. When the driver, or any automatic train control system, such as the TCMS Train Control Monitoring System, decide to release the brake due to an identified residual pressure on the brake cylinders, they perform an action that leads to the excitation of the electro -pneumatic Remote Release valve. In the excited condition, the electro -pneumatic remote release valve must perform two fundamental actions:

- avoid the flow of compressed air to the associated brake cylinders, also avoiding that the compressed air source to still be able to release additional air in other directions, such as at atmospheric pressure

- cause the associated brake cylinders to discharge at atmospheric pressure.

In figure 1 of EP2830918, shown as figure 6 in the present patent application, the electro pneumatic valves“Axel 1 Hold MV” and“Axel 2 Hold MV” operate as filling pilots towards the respective associated brake cylinders BCP1, BCP2 acting on the pneumatic valves 6, 7 and 16, 17, respectively. Furthermore, the electro -pneumatic valves“Axel 1 Vent MV” and “Axel 2 Vent MV” operate as venting pilots towards the respective associated brake cylinders BCP1, BCP2 acting on the pneumatic valves 6,7 and 16, 17, respectively. Also in this case the electro -pneumatic valves are used by the integrated control electronics simultaneously for the braking pressure control and anti-slip control functions.

Both devices described can find applications in braking systems for railway vehicles/trains operating at speeds above 200km/h. However, the introduction of additional electro pneumatic components to meet EN15595 §4.2.4.3“Special features of WSP systems for high speeds (v>200km/h)” and sub-chapters, compromises the levels of simplicity and integration achieved by said devices.

WO2019/053599 A1 describes a control system for service and emergency braking, however the above problems still remain unsolved.

Summary of the invention

An object of the present invention is to provide a solution that is able to meet the EN15595 §4.2.4.3 standard“Special features of WSP systems for high speeds (v>200km/h)” and sub chapters, without compromising the levels of simplicity and the solution integration.

The present invention is applicable to conventional systems.

In summary, the present invention therefore describes the use of an electro -pneumatic valve having a Remote Release function, present in a braking system, as an actuator to be assigned to a WRM device to fulfill the recommendations reported in EN15595 §4.2.4.3.2 and §4.2.4.3.3.

The above and other objects and advantages are achieved, according to an aspect of the invention, by a rotational monitoring system of at least one axle for a railway vehicle or train having the features defined in claim 1. Preferred embodiments of the invention are the defined in the dependent claims, whose content 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 rotational monitoring system of at least one axle for a railway vehicle or train according to the invention will now be described. Reference will be made to the accompanying drawings, in which:

Figure 1 shows a complete anti-slip system according to the prior art;

Figure 2 shows the detail of an anti-slip valve unit and the control circuits of an anti- slip device;

Figure 3 shows a known anti-slip valve assembly provided with redundant pilot valves; Figure 4 shows a known integrated railway braking system;

Figure 5 shows an embodiment of the present invention; and

Figure 6 shows a known integrated railway braking system.

Detailed description

Before explaining a plurality of embodiments of the invention in detail, it should be noted that the invention is not limited in its application to the construction details and to the configuration of the components presented in the following description or shown in the drawings. The invention can take other embodiments and be implemented or practically carried out in different ways. It should also be understood that the phraseology and terminology are for descriptive purpose and are not to be construed as limiting. The use of “include” and “comprise” and variations thereof are intended as including the elements cited thereafter and their equivalents, as well as additional elements and equivalents thereof.

Referring to figure 4, an integrated railway braking system includes an electro -pneumatic valve 20 for remote release, as explained above in detail, piloted by the electric signal RR coming from the outside.

This electro -pneumatic valve 20, when de-energized, constitutes a direct pneumatic passage between an electro-pneumatic filling valve 10 and a pilot chamber of a relay valve RV, in fact not interfering with the functionality of said electro -pneumatic filling valve 10.

Furthermore, the electro -pneumatic valve 20, when de-energized, does not interfere with an electro-pneumatic discharge valve 12. When the valve 20 is energized, as a consequence of an external command, said valve 20 blocks the outflow of air from an outlet port of the electro pneumatic filling valve 10, whatever the energized/de-energized condition of said electro pneumatic filling valve 10, and connects the pilot chamber of the relay valve RV to the atmosphere, whatever the energized/de-energized condition of the electro-pneumatic discharge valve 12. On the basis of the foregoing, advantageously, the remote release electro -pneumatic valve 20, if used as an actuator assigned to a WRM device, can comply with the recommendations set out in EN15595 §4.2.4.3.2 and §4.2.4.3.3.

In the present invention, the physical separation of the air discharge function between the electro-pneumatic valve 20 and the electro-pneumatic valve 12 constitutes a further advantage by providing total physical, as well as functional, redundancy between the anti- slip device and the WRM device.

A similar analysis performed on the diagram in figure 3 leads to the same conclusions.

Therefore, in an embodiment of the invention, a rotational monitoring system of at least one WRM axle for a railway vehicle or train is arranged to identify at least one axle controlled by it having an estimated instantaneous linear speed lower than a predetermined instantaneous linear limit speed. The rotational monitoring system of at least one WRM axle for a railway vehicle or train is also arranged to remove the braking force to one or more wheels of the axle identified to have an estimated instantaneous linear speed lower than said predetermined instantaneous linear limit speed, by canceling a pressure to brake cylinders associated with said at least one axle identified to have an estimated instantaneous linear speed lower than said predetermined instantaneous linear limit speed.

The cancellation of a pressure to brake cylinders associated with said at least one axle identified to have an estimated instantaneous linear speed lower than said predetermined instantaneous linear limit speed is obtained by acting on an electro -pneumatic valve RR arranged to perform a Remote Release function associated with the pneumatic circuits generating brake pressure for said brake cylinders and adapted to cancel a residual braking pressure.

A possible but not exclusive integration solution between the WRM device and the valve performing the Remote Release function is now described. Referring to figure 5, the WRM 501 device, for example consisting of a microprocessor system, generates a signal 502 which assumes logic level“1” when the WRM device 501 intends to energize the electro-valve RR which performs the Remote Release function, feeding the solenoid 503 thereof. The signal 502 activates a monostable circuit 507 whose output 508 assumes logic level“1” for a maximum time T following a transition 0 -> 1 by said signal 502 on its input 509. Output 508 again assumes logic value“0” after time T has run out or if signal 502 again assumes logic level“0” causing a reset of monostable 507 through its input“R” 510. The AND gate 511 conditions the signal 502 with the signal 508 and drives a driver 504 adapted to possibly translate the voltage level to supply the solenoid 505 of a relay, whose contact 506 supplies the solenoid 503 with the voltage Vrr, directly or through a dedicated power supply. The set of monostable circuit 507 and AND gate 511 limits the consecutive energization of the electro -pneumatic remote release valve to a maximum time T.

The contact 512 placed in parallel with the contact 506 is available to the driver or to the TCMS system to operate on the solenoid 503 of the electro -pneumatic valve performing the Remote Release function, in the usual way.

The relay consisting of solenoid 505 and contact 506 can be replaced by an opto-isolated switching element, for example but not exclusively by an opto-MOS, or by a functionally equivalent electronic circuit.

If the software of the WRM 501 device is developed at a SIL >3 safety level according to EN50128 standards, then the timeout function 507, 511 can be implemented directly within the software code of said WRM 501 device.

In other words, the electro-pneumatic valve RR arranged to perform a Remote Release function may be conditioned by a hardware timeout circuit 507, 511, or by a software timeout function, arranged to limit an excitation command of a solenoid 503 associated with said electro-pneumatic valve RR for a predetermined continuous time T.

The software timeout function can be performed directly within a software of the rotational monitoring system of at least one WRM axle. The predetermined continuous time T can take a value of 10 seconds. In fact, by setting T = 10s the recommendation reported in EN15595 §4.2.4.3.3 is satisfied. In a further aspect, the predetermined instantaneous linear limit speed is a function of a linear reference speed of the vehicle.

Various aspects and embodiments of a method for implementing a rotational monitoring system of at least one axle for a railway vehicle or train according to the invention have been described. It is understood that each embodiment may be combined with any other embodiment. The invention, moreover, is not limited to the described embodiments, but may be varied within the scope defined by the appended claims.