Patent Description:
The prior art will be described below with particular reference to the field of railway vehicles. Nevertheless, that which is described in the following may also apply, where possible, to vehicles in other fields.

Braking systems and suspension systems for railway vehicles for passenger transport are powered by compressed air.

A system for generating compressed air according to the prior art is illustrated in <FIG>.

Such system for generating compressed air <NUM> comprises a motor <NUM> whose motor shaft <NUM> supplies a driving torque to a motor shaft <NUM> of a compressor <NUM> through an elastic coupling <NUM>.

Through an inlet <NUM>, the compressor <NUM> draws air at atmospheric pressure, compresses it and, through a pneumatic connection <NUM> and a non-return valve <NUM>, supplies a dryer unit <NUM>. The dryer unit <NUM> has the purpose of removing the liquid component and the vapor of the water derived from the compression of humid air and supplying dried air to a main reservoir <NUM> through a second duct <NUM> and a second non-return valve <NUM>.

A control unit <NUM> receives an electrical power supply <NUM> and measures a pressure in the main reservoir <NUM> by means of a pressure transducer <NUM>.

When the pressure in the main reservoir <NUM> assumes a value less than or equal to a minimum value Pmin, the control unit <NUM> supplies electrical power to the electric motor <NUM>.

When the pressure in the main reservoir <NUM> assumes a value equal to or greater than a maximum value Pmax, the control unit <NUM> cuts off the electrical supply to the electric motor <NUM>.

In the railway sector, the minimum value Pmin generally assumes values of between 6bar and <NUM> bar, and the maximum value Pmax generally assumes values of between 9bar and 10bar.

It is prior art that the system for generating compressed air <NUM> is integrated inside an acoustically insulated metal structure provided with damping connections to the railway vehicle in order to reduce the noise emitted and the vibrations transmitted to a body of the railway vehicle, respectively.

Through a distribution duct <NUM>, the compressed air stored in the main reservoir <NUM> is supplied to at least one user system <NUM>, <NUM>, such as, for example, the braking system, the suspension system, the toilets, the pantographs, the doors.

<FIG> illustrates a typical railway convoy <NUM> for carrying passengers.

Two compressed air generation systems <NUM> and <NUM>, corresponding to the compressed air generation system <NUM> of <FIG>, supply compressed air to a main duct <NUM>, which in turn supplies a main reservoir <NUM> through a non-return valve <NUM>.

From the main reservoir <NUM> various systems <NUM>, <NUM>, <NUM>, such as for example the braking system, suspensions, toilets, draw compressed air for their operation.

Two compressed air generation systems <NUM>, <NUM> are considered necessary for redundancy reasons, i.e. to guarantee a permanent supply of compressed air even in the event of failure of one of the two compressed air generation systems <NUM>, <NUM> during operational daily service.

A control system <NUM> alternatively enables the two compressed air generation systems <NUM>, <NUM> by means of the supply signals <NUM>, <NUM>, this disadvantageously meaning that one of the two compressed air generation systems <NUM>, <NUM> is on average unused throughout service.

The weight of each compressed air generation system <NUM>, <NUM> often exceeds <NUM>, disadvantageously requiring an unnecessary expenditure of energy to accelerate the mass thereof. This energy is then definitively lost during braking due to poor efficiency of the regenerative braking system or intrinsically dissipative mechanical friction braking.

In general, a single compressed air generation system may supply compressed air at full capacity at the total cost of two systems.

<CIT> discloses a method and a system for supplying compressed air to a vehicle as required. However, the above problems remain unsolved.

An object of the present invention is to provide a method and a system for generating compressed air of at least one vehicle, in particular at least one railway vehicle, which reduces the weight and the cost compared to compressed air generation systems according to the prior art, while respecting the redundancy requirement.

The aforesaid and other objects and advantages are achieved, according to an aspect of the invention, by a method for generating compressed air of at least one vehicle having the features defined in claim <NUM> and by a compressed air generation system of at least one vehicle having the features defined in claim <NUM>. 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.

The functional and structural features of some preferred embodiments of a system for generating compressed air of at least one vehicle according to the invention will now be described. Reference is made to the accompanying drawings, in which:.

Before describing 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 is able to assume other embodiments and to 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 their variations is to be understood as encompassing the elements set out below and their equivalents, as well as additional elements and the equivalents thereof.

In a first embodiment, a method for generating compressed air of at least one vehicle, in particular a railway vehicle, comprises the step of:.

Preferably, the method further comprises the step of measuring a pressure value indicative of the internal pressure of a main reservoir <NUM> arranged to accumulate compressed air generated by said first compressor <NUM> and said second compressor <NUM>.

The pressure value inside said main reservoir <NUM> may assume over time a value included in a range of pressures. Such range of pressures includes a null value, a first predetermined pressure value Pmin (greater than said null value) and a second predetermined pressure value Pmax, greater than said first predetermined pressure value Pmin.

Preferably, when the pressure value in said main reservoir <NUM> is lower than the first predetermined pressure value Pmin, step a) may comprise:.

Preferably, in addition or alternatively to what has been said for the condition in which said pressure value is lower than the first predetermined pressure value Pmin, when the pressure value in said main reservoir <NUM> is equal to or greater than the second predetermined value pressure Pmax, step a) may comprise:.

Preferably, in addition or alternatively to what has been said for the condition in which said pressure value is lower than the first predetermined pressure value Pmin and for the condition in which said pressure value is equal to or greater than the second predetermined value of pressure Pmax, when the pressure value in said main reservoir <NUM> is equal to the first predetermined pressure value Pmin or comprised between the first predetermined pressure value Pmin and the second predetermined pressure value Pmax, step a) may selectively comprise:.

In another aspect of the invention, with reference to <FIG>, a first embodiment of a system for generating compressed air of at least one vehicle, particularly at least one railway vehicle, is illustrated.

Such system for generating compressed air of at least one vehicle comprises an electric motor <NUM> arranged to generate a driving torque.

The system for generating compressed air of at least one vehicle further comprises a first coupling means <NUM>, arranged to selectively assume a first state in which it connects said electric motor <NUM> to said first compressor <NUM> or a second state in which it disconnects said motor electric motor <NUM> from said first compressor <NUM>, and a second coupling means <NUM>, arranged to selectively assume a first state in which it connects said electric motor <NUM> to said second compressor <NUM> or a second state in which it disconnects said electric motor <NUM> from said second compressor <NUM>.

The compressed air generation system of at least one vehicle further comprises a control means <NUM> arranged to control the transition between the first state and the second state, and vice versa, of said first coupling means <NUM> and the transition between the first state and the second state, and vice versa, of said second coupling means <NUM>, so that said driving torque generated by said electric motor <NUM> is selectively supplied to the first compressor <NUM> or to the second compressor <NUM> or simultaneously to said first compressor <NUM> and to said second compressor <NUM>.

For example, the control means may be or comprise at least one of a control unit, a processor, a microprocessor, a controller, a microcontroller, an FPGA, a PLC, or the like.

Preferably, the compressed air generation system of at least one vehicle may comprise a main reservoir <NUM> arranged to store compressed air generated by said first compressor <NUM> and said second compressor <NUM>, and a pressure sensor means arranged to measure a pressure value inside said main reservoir <NUM>.

The pressure value inside said main reservoir <NUM> may assume a pressure value included in a range of pressures. Such range of pressures includes a null value, a first predetermined pressure value Pmin (greater than said null value) and a second predetermined pressure value Pmax, greater than said first predetermined pressure value Pmin.

The pressure sensor means may be or comprise, for example, a pressure sensor or a pressure measuring device, or the like.

Preferably, when the pressure value measured by said pressure sensor means is lower than the first predetermined pressure value Pmin, the control means <NUM> may be arranged to:.

By higher than said first predetermined pressure value Pmin, for example, it may be understood a value equal to the second predetermined pressure value Pmax higher than said first predetermined pressure value Pmin, or a value between the first predetermined pressure value Pmin and the second predetermined pressure value Pmax.

For example, the control means <NUM> may:.

Preferably, when the pressure value measured by the pressure sensor means is lower than the first predetermined pressure value Pmin, said control means <NUM> may be arranged to:.

In other words, with reference to the exemplary operating cycle of <FIG>, in an instant T0 of ignition of the vehicle or convoy, for example railway vehicle or railway convoy, the control means <NUM> (e.g. a control unit) may control the first coupling means <NUM> (e.g. a first electromechanical clutch) and the second coupling means <NUM> (e.g. a second electromechanical clutch <NUM>) in their first state in which they transmit the driving torque of the electric motor <NUM> to the first compressor <NUM> and to the second compressor <NUM>, and may control the electric motor <NUM> to rotate at a first speed V1, so as to generate a driving torque having a first torque value, suitable for bringing the pressure in the main reservoir <NUM> to the first predetermined pressure value Pmin as fast as possible.

In addition or as an alternative to what has been said for the condition in which said pressure value is lower than the first predetermined pressure value Pmin, preferably, when the pressure value measured by said pressure sensor means is equal to the first predetermined pressure value Pmin or comprised between the first predetermined pressure value Pmin and the second predetermined pressure value Pmax, the control means <NUM> may be selectively arranged to:.

For example, the control means <NUM> may be arranged to selectively:.

For example, referring to the exemplary operating cycle of <FIG>, following the instant T2 in which the second predetermined pressure value Pmax is reached, the pressure in the main reservoir <NUM> may begin to drop towards the first predetermined pressure value Pmin due to a request for compressed air by one or more users <NUM>, <NUM>, <NUM>. When at instant T3 the pressure in the main reservoir <NUM> has reached first predetermined pressure value Pmin (i.e. when it is necessary to bring the pressure in the main reservoir from the first predetermined pressure value Pmin to the second predetermined pressure value Pmax), the control unit <NUM> may choose which of the first compressor <NUM> and the second compressor <NUM> is to be coupled to the electric motor <NUM>, and may couple the selected compressor to the electric motor <NUM> by controlling the coupling means (e.g. the electromechanical clutch) associated with the selected compressor, in its first state in which it transmits driving torque from the electric motor <NUM> to the selected compressor, and may for example control the electric motor <NUM> to rotate at a second speed V2, less than or equal to said first speed V1, i.e. V2≤V1. The other unselected compressor is not coupled to the electric motor <NUM> by controlling the coupling means (e.g. the electromechanical clutch) associated with the unselected compressor, in its second state in which it does not transmit driving torque from the electric motor <NUM> to the unselected compressor. In the embodiment described above, the preselected compressor may be any one between the first compressor <NUM> and the second compressor <NUM>.

Preferably, according to a first criterion, the control means <NUM> may be arranged to measure a first overall activation time of said first compressor <NUM> and to measure a second overall activation time of said second compressor <NUM>.

When the pressure value measured by said pressure sensor means is equal to the first predetermined pressure value Pmin or comprised between the first predetermined pressure value Pmin and the second predetermined pressure value Pmax, and the first overall activation time of said first compressor <NUM> is greater than said second overall activation time of said second compressor <NUM>, said control means <NUM> may be arranged to:.

For example, the control means <NUM> may be arranged to:.

When, instead, the pressure value measured by said pressure sensor means is equal to the first predetermined pressure value Pmin or comprised between the first predetermined pressure value Pmin and the second predetermined pressure value Pmax, and the first overall activation time of said first compressor <NUM> is shorter than said second overall activation time of said second compressor <NUM>, said control means <NUM> may be arranged to:.

In other words, in the first criterion just described, when it is necessary to bring the pressure in the main reservoir from the first predetermined pressure value Pmin to the second predetermined pressure value Pmax, the control means <NUM> (e.g. the control unit) may count the cumulative usage time of the first compressor and the second compressor and choose to connect the compressor with the shortest usage time to the electric motor, in order to better equalize the consumption of the components of the first compressor and the second compressor, so as to reach the deadline of the maintenance cycle at the same time.

Preferably, according to a second criterion, the control means <NUM> may be arranged to measure a first overall activation time of said first compressor <NUM> and to measure a second overall activation time of said second compressor <NUM>. The control means <NUM> may be arranged to:.

In this case, in said first inhibition time period, when the pressure value measured by said pressure sensor means is equal to the first predetermined pressure value Pmin or comprised between the first predetermined pressure value Pmin and the second predetermined pressure value Pmax, said control means <NUM> may be arranged to:.

In said second inhibition time period, when the pressure value measured by said pressure sensor means is equal to the first predetermined pressure value Pmin or comprised between the first predetermined pressure value Pmin and the second predetermined pressure value Pmax, said control means <NUM> may be arranged to:.

In other words, in the second criterion just described, the control unit <NUM> may re-count the cumulative usage time of the first compressor and second compressor and, for example at the start of the operating day, the control unit <NUM> may choose the compressor that has the shortest cumulative usage time and, when it is necessary to bring the pressure in the main reservoir from the first predetermined pressure value Pmin to the second predetermined pressure value Pmax, it may use it for a predetermined period, inhibiting the other compressor in such predetermined period (e.g. all day).

Preferably, according to a third criterion, said control unit may be arranged to define first time-intervals in which activation of the first compressor <NUM> is prevented and second time-intervals in which activation of second compressor <NUM> is prevented. Said first time-intervals and said second time-intervals may be alternated to each other over time. When in one of said first time-intervals, the pressure value measured by said pressure sensor means is equal to the first predetermined pressure value Pmin or comprised between the first predetermined pressure value Pmin and the second predetermined pressure value Pmax, said control means <NUM> may be arranged to:.

Moreover, when in one of said second time-intervals, the pressure value measured by said pressure sensor means is equal to the first predetermined pressure value Pmin or comprised between the first predetermined pressure value Pmin and the second predetermined pressure value Pmax, said control means <NUM> may be arranged to:.

In other words, in the third criterion just described, when it is necessary to bring the pressure in the main reservoir from the first predetermined pressure value Pmin to the second predetermined pressure value Pmax, the control unit <NUM> may alternatively use the two compressors at alternate regular periods, for example non-exclusive on alternate days. In this way, the selected compressor may be kept for a period, always at temperature to limit the formation of condensation inside the compressor due to excessive cooling and the wear of the first compressor and the second compressor is balanced.

Preferably, it may apply to all the embodiments described above that when the pressure value measured by said pressure sensor means is between the first predetermined pressure value Pmin and the second predetermined pressure value Pmax, which is greater than the first predetermined pressure value Pmin, the control means <NUM> may be arranged to:.

Preferably, in addition or alternatively to what has been said for the condition in which said pressure value is lower than the first predetermined pressure value Pmin and for the condition in which said pressure value is equal to the first predetermined pressure value Pmin or comprised between the first predetermined pressure value Pmin and the second predetermined pressure value Pmax, when the pressure value measured by said pressure sensor means is equal to or greater than the second predetermined pressure value Pmax, greater than said first predetermined value of pressure Pmin, said control means <NUM> may be arranged to:.

In other words, with reference to the exemplary operating cycle of <FIG>, when at an instant T2 the pressure value Pmax is reached, the control means <NUM> may turn off the electric motor <NUM> and control the first coupling means <NUM> (e.g. the first electromechanical clutch) and the second coupling means <NUM> (e.g. the second electromechanical clutch <NUM>) in their second state in which they do not transmit driving torque from the electric motor <NUM> to the first compressor <NUM> and the second compressor <NUM>, respectively.

Preferably, when the pressure value measured by said pressure sensor means is equal to or higher than the second predetermined pressure value Pmax, the control means <NUM> may be arranged to:.

Preferably, the compressed air generation system of at least one vehicle may comprise a first air dryer means <NUM> and a second air dryer means <NUM>. The first air dryer means <NUM> may be arranged to receive the compressed air generated by the first compressor <NUM> and generate first dried compressed air to be supplied to said main reservoir <NUM>. The second air dryer means <NUM> may be arranged to receive the compressed air generated by the second compressor <NUM> and generate second dried compressed air to be supplied to said main reservoir <NUM>.

For example, the first compressor <NUM> may feed a first dryer <NUM>, which in turn may feed the main reservoir <NUM> through a non-return valve <NUM>. The second compressor <NUM> may feed a second dryer <NUM>, which in turn feeds the main reservoir <NUM> through a non-return valve <NUM>.

Or, the compressed air generation system of at least one vehicle may comprise only one air dryer means. In this case, the air dryer means may be arranged to receive compressed air generated by the first compressor <NUM>, receive compressed air generated by the second compressor <NUM> and generate dried compressed air to be supplied to said main reservoir <NUM>.

For example, referring to <FIG>, the first compressor <NUM> and the second compressor <NUM> may supply compressed air to a single dryer <NUM>, for example through two non-return valves <NUM>, <NUM>, respectively.

Preferably, the electric motor <NUM> may comprise a first drive shaft <NUM> arranged to transmit driving torque to a first compressor <NUM> through the first coupling means <NUM> and a first mechanical coupling <NUM>, and a second drive shaft <NUM>, arranged to be integral with the said first drive shaft <NUM> and to transmit the driving torque to the second compressor <NUM> through the second coupling means <NUM> and a second mechanical coupling <NUM>.

Preferably, in a further embodiment, the electric motor <NUM> may comprise a drive shaft <NUM> on which the first coupling means <NUM> and the second coupling means <NUM> are arranged to be bound. In this case, the compressed air generation system of at least one vehicle may comprise a first pulley <NUM> and a second pulley <NUM>. The first pulley <NUM> may be arranged to be mechanically bound to a shaft <NUM> of the first compressor <NUM>, and the second pulley <NUM> may be arranged to be mechanically bound to a shaft <NUM> of a second compressor <NUM>. The first coupling means <NUM>, <NUM> may be arranged to transmit driving torque to the first pulley <NUM> by at least one drive belt <NUM>, and the second coupling means <NUM>, <NUM> may be arranged to transmit driving torque to the second pulley <NUM> by at least one drive belt <NUM>.

Preferably, the first coupling means <NUM> may be an electromechanical clutch.

Preferably, the second coupling means <NUM> may also be an electromechanical clutch.

For example, the first predetermined pressure value Pmin may generally assume values of between 6bar and <NUM> bar, and the second predetermined pressure value Pmax may generally assume values of between 9bar and 10bar.

In a first implementation example, a compressed air generation system <NUM> may comprise an electric motor <NUM> having a first drive shaft <NUM> for transmitting driving torque to a first compressor <NUM> through a first coupling means <NUM>, such as for example a first electromechanical clutch, and a first mechanical coupling <NUM>.

Furthermore, the electric motor <NUM> may be provided with a second drive shaft <NUM>, integral with the first drive shaft <NUM>, for transmitting driving torque to a second compressor <NUM> through a second coupling means <NUM>, such as for example a second electromechanical clutch, and a second mechanical coupling <NUM>.

The first compressor <NUM> may feed a first dryer means <NUM>, for example a first dryer, which in turn may feed the main reservoir <NUM> through a non-return valve <NUM>.

The second compressor <NUM> may feed a second dryer means <NUM>, for example a second dryer, which in turn may feed the main reservoir <NUM> through a non-return valve <NUM>.

The control means <NUM>, for example a control unit, may be arranged to:.

The pressure sensor means <NUM>, for example a pressure transducer <NUM>, may measure the pressure inside the main reservoir <NUM> and send its value <NUM> to the control unit <NUM>.

In a second implementation example, with reference to <FIG>, the electric motor <NUM> may have a drive shaft <NUM> on which the first coupling means <NUM>, for example a first electromechanical clutch, and a second coupling means, for example a second electromechanical clutch <NUM>, are mechanically bound. Both coupling means <NUM>, <NUM> may have the peripheral shape of a pulley for driving at least one drive belt. A first pulley <NUM> may be mechanically bound to a shaft <NUM> of the first compressor <NUM>, and a second pulley <NUM> may be mechanically bound to a shaft <NUM> of a second compressor <NUM>.

The first coupling means <NUM> may transmit driving torque to the first pulley <NUM> by means of at least one drive belt <NUM>. The second coupling means <NUM> may transmit driving torque to the second pulley <NUM> by means of at least one drive belt <NUM>.

The control means <NUM>, for example a control unit <NUM>, may be arranged to:.

What has been described above for at least one vehicle, for example railway vehicle, may be applied similarly for a plurality of railway vehicles connected to each other to form a convoy, for example a railway convoy.

As described above, the present invention is particularly applicable to the field of railway vehicles/convoys that travel on railway tracks. For example, a vehicle referred to herein may be a locomotive or a wagon, and a route/section may include rails on which the wheels of the locomotive roll. The embodiments described herein are not intended to be limited to vehicles on tracks. For example, the vehicle may be a car, a truck (for example a highway semi-trailer truck, a mining truck, a truck for transporting timber or the like) or the like, and the route may be a road or a trail. For example, a convoy may comprise a plurality of such vehicles connected or associated with each other.

Claim 1:
Method for generating compressed air of at least one vehicle, in particular at least one railway vehicle, comprising the step of:
a) selectively connecting a first compressor (<NUM>), or a second compressor (<NUM>), or simultaneously said first compressor (<NUM>) and said second compressor (<NUM>), to an electric motor (<NUM>) arranged to generate a driving torque.