Patent Description:
The most recent trains for passenger rail transport are made up of fixed trainsets. The definition of "fixed trainset" indicates that the configuration of the vehicle is defined in the design phase, where the composition defines which vehicles will be equipped with traction drive, and which vehicles will be towed. After the construction and composition of the train, said train will be broken down into individual vehicles only in case of maintenance due to serious structural damage associated with one of the vehicles making up the train.

<FIG> illustrates a non-exclusive example of a fixed trainset <NUM> consisting of five cars <NUM>,.

It is state of the art that each railway vehicle making up the train <NUM> is equipped with a local HVAC (Heating, Ventilation, Air Conditioning) system, that is, a system for heating, ventilation and air conditioning of the passenger compartment.

It is also known that in the railway passenger transport system, the braking systems use compressed air appropriately injected into brake cylinders to generate braking force. Compressed air is generated by one or more compressors. Compressors for this purpose are available with different air flow rates. Generally two compressors <NUM>, <NUM> are installed, as illustrated by way of non-exclusive example in <FIG>. The dimensioning of the flow rate is derived from the filling speed requirements of the empty system at the daily start-up of the train, and from redundancy criteria in case of failure of at least one of the installed compressors.

It is known that the HVAC systems <NUM>,. , <NUM> are each integrated into self-contained structures, typically designed to be installed on the train roof. <FIG> illustrates a real <NUM>:<NUM> scale example of an HVAC system for regional trains.

<FIG> shows how inside an HVAC system, in addition to various other devices, there is a compressor <NUM> used for compressing the refrigerant gas, said refrigerant gas exchanged with the rest <NUM> of the HAVC system. The compressor <NUM> is mechanically connected to a motor <NUM> by means of a shaft <NUM>. A mechanical joint, not shown in the figure, may be interposed between the motor <NUM> and the compressor <NUM> to compensate for misalignments of the two resulting half-shafts. An electronic unit <NUM> receives electrical signals <NUM> coming from sensors forming part of the HVAC system <NUM> and electrical signals <NUM> coming from the passenger compartments to be conditioned. The electronic unit <NUM> controls a power supply device <NUM>. The power supply device <NUM> receives electrical energy <NUM> distributed on board the vehicle and powers the motor <NUM>. Said power supply device <NUM> may be a simple remote control switch or a power frequency control device, to control said motor <NUM> with speed control criteria. A recurring power value for the motor <NUM> is on the scale of <NUM> KVA.

An HVAC system, similar in size to that illustrated in <FIG>, usually has a weight on the scale of <NUM>.

It is known that AGTU systems <NUM>, <NUM> are each integrated into self-contained structures, typically designed to be installed on the roof of the associated vehicle, or suspended under the body of the associated vehicle. <FIG> shows a real example in <NUM>:<NUM> scale of an AGTU system for passenger vehicles.

<FIG> shows how inside an AGTU system, in addition to various other devices, there is a compressor <NUM> used for compressing air. The compressed air is sent to a dryer <NUM> and subsequently accumulated in a main tank <NUM>, from which it is then distributed to the users through a main brake pipe <NUM>.

The compressor <NUM> is mechanically connected to a motor <NUM> by means of a resilient joint <NUM>. The resilient joint <NUM> is used to compensate for misalignments of the two resulting half-shafts. A pressure switch <NUM> having a hysteresis turns on a power supply device <NUM> at a minimum pressure value, by way of non-exclusive example between <NUM> bar and <NUM> bar. The pressure switch <NUM> turns off the power supply device <NUM> at a maximum pressure value, by way of non-exclusive example, between <NUM> bar and <NUM> bar. The power supply device <NUM> may be a remote control switch, or more rarely, a power frequency control device, to control the motor <NUM> with speed control criteria, known as "soft start.

A typical power/flow rate ratio for the motor <NUM> is on the scale of <NUM> KVA for a flow rate of <NUM>/min. For a real case such as a passenger train as illustrated in <FIG>, for each AGTU system <NUM>, <NUM> a flow rate between <NUM>/min and <NUM>/min is required, i.e. each motor <NUM> is required to have a power between about <NUM> KVA and <NUM> KVA.

An AGTU system, of similar dimensions to that illustrated in <FIG>, has a weight on the scale of <NUM>. The weight of the associated motor <NUM> is on the scale of <NUM>. The weight of the support frame for the complete AGTU may vary from <NUM> to <NUM>.

In order to reduce the sources of pollution such as lubricating oils inside the compressors, the technology known as "oil-free" is currently preferred. The "oil-free" solution further improves the so-called "Life Cycle Cost" LCC, that is the total life cycle cost of the compressor, as the "oil-free" solution eliminates the periodic maintenance cycles linked to replacing the lubricating oil.

The aforementioned air flow rates may be reached, through "oil-free" technologies, exclusively by means of piston compressors, characterized by high acoustic noise and high vibrations induced to the load-bearing structures, or to the cars of the vehicles to which they are attached.

There are known "oil-free" alternatives to piston compressors, known as "scroll" compressors, characterized by a purely rotary behavior, free from acoustic noise and harmful mechanical vibrations. However, these "scroll" compressors do not reach high flow rates, on the order of <NUM>/min. Wanting to use scroll compressors, it would be necessary to insert many units with the additional costs of motors and AGTU support frames, leading to an increase in weight and the required space available for their installation.

<CIT>relates to a rail vehicle compressor system and method for controlling the same uses a compressor driven by an electrical machine via a drive shaft to produce compressed air for at least one compressed air tank. However, the problems described above remain unsolved.

An object of this invention is to provide a solution which allows the integration of AGTU systems and HVAC systems forming part of at least one railway vehicle, or more railway vehicles of the same railway train.

A further object is to provide a solution which allows the number of motors necessary for the generation of compressed air and for the air conditioning of at least one railway vehicle, or several railway vehicles of the same railway train, to be reduced.

The aforesaid and other objects and advantages are achieved, according to an aspect of the invention, by a system for the generation of compressed air and for air conditioning 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 this description.

The functional and structural features of some preferred embodiments of an electronic control system for emergency and service braking according to the invention will now be described. Reference is made to the accompanying drawings, wherein:.

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 construction details and configuration of the components presented in the following description or illustrated in the drawings. The invention is capable of assuming other embodiments and of being 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 are to be understood as encompassing the elements set out below and their equivalents, as well as additional elements and the equivalents thereof.

This patent relates to a solution for the integration of AGTU systems and HVAC systems forming part of the same train.

<FIG> illustrates a system for the generation of compressed air and for air conditioning according to the invention.

In particular, a single electric motor <NUM> may be selectively coupled to a first compressor <NUM> for compressed air by a first coupling means <NUM>.

The first compressor <NUM> is arranged to compress the air taken in at atmospheric pressure. The air is sent to a dryer <NUM> and subsequently accumulated in a main tank <NUM>, from which it is then distributed to various users through a main brake pipe <NUM>. The users may, by way of non-exclusive example, be the train braking system.

The single electric motor <NUM> may be further selectively coupled to a second compressor <NUM> by a second coupling means <NUM>.

The second compressor <NUM> is joined to an HVAC <NUM>,. , <NUM> system.

The second compressor <NUM> is arranged to compress the refrigerant gas, which is exchanged with the rest of the HAVC system <NUM>.

In this way, the system <NUM> comprises a single electric motor <NUM> arranged to generate a mechanical torque to be selectively supplied to the first compressor <NUM> and/or to the second compressor <NUM>.

The mechanical torque will be selectively supplied to the first compressor <NUM> and/or to the second compressor <NUM> as a function of a first electrical signal <NUM> generated by a pressure measurement device <NUM> and indicative of a pressure present in the main brake pipe <NUM>, or in the main tank <NUM>, and of at least a second electrical signal <NUM> coming from the air conditioning system <NUM> and indicative of a temperature value or a pressure value or a humidity value, and at least a third electrical signal <NUM> indicative of a temperature of an environment to be conditioned of the railway vehicle.

The system may comprise an electronic control unit <NUM> arranged to generate a first control signal <NUM> for the first coupling means <NUM> so as to couple or uncouple the electric motor <NUM> and the first compressor <NUM>, and a second control signal <NUM> for a second coupling means <NUM> so as to couple or uncouple the electric motor <NUM> and the second compressor <NUM>.

The first coupling means <NUM> and the second coupling means <NUM> may be respective electromagnetic joints.

In this case, the first coupling means <NUM>, i.e. the electromagnetic joint, couples/uncouples a first half-shaft <NUM> associated to the first compressor <NUM> and a second half-shaft <NUM> associated to the electric motor <NUM>, as a function of the first electrical command <NUM> generated by the electronic control unit <NUM>.

When the first coupling means <NUM> connects the first and second half-shafts <NUM>, <NUM>, the electric motor <NUM> transmits mechanical torque to the first compressor <NUM>. On the other hand, when the first coupling means <NUM> decouples the first half-shaft <NUM> and the second half-shaft <NUM>, the first compressor <NUM> receives no mechanical torque from the electric motor <NUM>.

The second coupling means <NUM>, i.e. the electromechanical joint, couples/uncouples a third half-shaft <NUM> and a fourth half-shaft <NUM> as a function of the second electrical command <NUM> generated by the electronic control unit <NUM>. The third half-shaft <NUM> is associated to the electric motor <NUM> and the fourth half-shaft <NUM> is associated to the second compressor <NUM>.

When the second coupling means <NUM> couples the second half-shaft <NUM> and the third half-shaft <NUM>, the electric motor <NUM> transmits mechanical torque to the second compressor <NUM>. On the other hand, when the second coupling means <NUM> decouples the third half-shaft <NUM> and the fourth half-shaft <NUM>, the second compressor <NUM> receives no mechanical torque from the electric motor <NUM>.

For example, but not exclusively, the electromechanical joint of the first coupling means <NUM> and the electromechanical joint of the second coupling means <NUM> may each be an electromagnetic clutch.

Still observing <FIG>, the electronic control unit <NUM> receives the first electrical signal <NUM> generated by the pressure measurement device <NUM>.

The pressure measurement device <NUM> may be, for example, but not exclusively, a pressure switch with hysteresis. In this case, the first electrical signal <NUM> may indicate the need to activate the first compressor <NUM>, and therefore the need to supply the mechanical torque generated by the electric motor to the first compressor <NUM>, when the first electrical signal <NUM> indicates that the pressure on the main brake pipe <NUM>, measured by the pressure measurement device <NUM>, reaches a minimum pressure, by way of non-exclusive example between <NUM> bar and <NUM> bar.

In another case, the pressure measurement device <NUM> may be, by way of non-exclusive example, a pressure sensor generating a first electrical signal <NUM> proportional to the pressure value measured on the main brake pipe <NUM>. In this case, the first electrical signal <NUM> may indicate the need to deactivate the first compressor <NUM>, and therefore does not indicate the need to supply the mechanical torque generated by the electric motor to the first compressor <NUM>, when the pressure on the main brake pipe <NUM>, measured by the pressure measurement device <NUM>, reaches a maximum pressure, by way of non-exclusive example between <NUM> bar and <NUM> bar.

Furthermore, the electronic control unit <NUM> also receives the at least one second electrical signal <NUM> coming from the at least one sensor belonging to the HVAC system <NUM> and the at least one third electrical signal <NUM> coming from the at least one temperature sensor in a passenger compartment of the train to be conditioned. Obviously, the second electrical signals <NUM> may be a plurality and come from several sensors, each suitable for measuring a pressure or temperature or humidity relating to the HVAC system <NUM>, and the third electrical signals <NUM> may be a plurality and come from a plurality of temperature sensors arranged in various passenger compartments to be conditioned of the railway vehicle.

The electronic control unit <NUM> may control a power supply device <NUM> arranged to receive electrical power <NUM> distributed on board the railway vehicle and to power the motor <NUM>.

The power supply device <NUM> may be for example a simple remote control switch or a power frequency control device, also known by the technical term of "inverter," for controlling the electric motor <NUM> with speed control criteria.

The electronic control unit <NUM> may activate the power supply device <NUM>, and consequently the electric motor <NUM>, if the first electrical signal <NUM> indicates the need to activate the first compressor <NUM>, or if at least one of either the second electrical signal <NUM> or the third electrical signal <NUM> indicates the need to activate the second compressor <NUM>, and therefore indicates the need to supply the mechanical torque generated by the electric motor to the second compressor <NUM>.

In the event of the simultaneous absence of a request for activation of the respective compressors <NUM>, <NUM> by the first electrical signal <NUM>, and the second electrical signal <NUM> and the third electrical signal <NUM>, the electronic control unit <NUM> deactivates the power supply device <NUM>, switching off the electric motor <NUM>.

Summarizing what has been set out above, the electronic control unit <NUM> continuously analyzes the first electrical signal <NUM> and the second electrical signal <NUM> and the third electrical signal <NUM>, and decides when to activate the power supply device <NUM>, and consequently the electric motor <NUM>, and which one of either the first coupling means <NUM> or the second coupling means <NUM> to activate to supply suitable mechanical torque, generated by the electric motor, to the first compressor <NUM> and/or to the second compressor <NUM>, respectively.

In one possible embodiment, the electric motor <NUM> is scaled to be able to supply a mechanical torque equivalent to the sum of the peak mechanical torques of the first and second compressors <NUM>, <NUM>, so that they may be activated simultaneously.

In this embodiment, the electronic control unit <NUM> activates the first coupling means <NUM> if the first electrical signal <NUM> indicates the need to activate the first compressor <NUM>, and activates the second coupling means <NUM> if at least one of either the second electrical signal <NUM> or the third electrical signal <NUM> indicates the need to activate the second compressor <NUM>. In case of the simultaneous presence of an activation request by the first electrical signal <NUM> and the second electrical signal <NUM> or third electrical signal <NUM>, of the respective compressors <NUM>, <NUM>, the electronic control unit <NUM> simultaneously activates both the first coupling means <NUM> and the second coupling means <NUM> so as to connect the electric motor <NUM> both to the first compressor <NUM> and to the second compressor <NUM>.

The electronic control unit <NUM> will deactivate the first coupling means <NUM> when the first electrical signal <NUM> indicates that the maximum pressure has been reached at the main tank <NUM>, i.e. it does not indicate the need to supply the mechanical torque generated by the electric motor to the first compressor <NUM>, or will deactivate the second coupling means <NUM> if at least one of either the second electrical signal <NUM> or the third electrical signal <NUM> indicates that the compression of the refrigerant gas is not necessary, i.e. it does not indicate the need to supply the mechanical torque generated by the electric motor to the second compressor <NUM>.

In a further possible embodiment, the electric motor <NUM> is scaled to provide the greater of either the peak mechanical torque of the first compressor <NUM> or the peak mechanical torque of the second compressor <NUM>.

In this further embodiment, since the electric motor <NUM> may supply only the greater of the mechanical torques characteristic of the two compressors <NUM>, <NUM>, in the event of simultaneous requests to activate the electric motor <NUM> from the first electrical signal <NUM> and at least one of either the second electrical signal <NUM> or the third electrical signal <NUM>, the electronic control unit <NUM> alternately activates the first coupling means <NUM> and the second coupling means <NUM>, according to pre-loaded strategies, for example in a non-volatile memory <NUM> in the form of executable code or operating parameters, so as to alternately connect the electric motor <NUM> to the first compressor <NUM> and to the second compressor <NUM>.

For example, but not exclusively, a first strategy consists in giving absolute priority to the mechanical torque request coming from the first electrical signal <NUM> for the first compressor <NUM>, since it is normally linked to the pressure request from the braking system.

In the presence of a mechanical torque request from the first electrical signal <NUM>, the electronic control unit <NUM> carries out the following steps:.

When the pressure at the main tank <NUM> has reached the predetermined maximum value, the electronic control unit <NUM> performs the following steps:.

If, during the phase wherein the second coupling means <NUM> is activated, a request occurs again from the first electrical signal <NUM>, the cycle starts again.

By way of non-exclusive example, a second strategy consists in giving temporary priority to the activation request coming from the first electrical signal <NUM>, as it is normally linked to the pressure request from the braking system. This second strategy requires the pressure measurement device <NUM> to be comprised of a linear pressure transducer capable of supplying, as a first electrical signal <NUM>, a continuous pressure value signal.

During the described sequence, any return of the first electrical signal <NUM> to the value indicating a minimum pressure at the main tank <NUM> reactivates the sequence from the beginning.

The first and second compressors <NUM> and <NUM> may be volumetric compressors. It is well known that the mechanical torque required by a volumetric compressor may be considered proportional to the pressure at its output, unless torque contributions are necessary to overcome the friction of said compressor.

Based on this definition, it may be defined that the torque required by the first compressor <NUM> when the pressure at the main tank <NUM> is at its predetermined minimum value is less than the torque required by the first compressor <NUM> when the pressure at the main tank <NUM> has reached the predetermined maximum value. A similar consideration may be made for the second compressor <NUM>. It is therefore possible that, if both the first and second compressors <NUM>, <NUM> are at their respective minimum operating pressures, the sum of the mechanical torques necessary to move said compressors is lower than the maximum torque that may be supplied by the electric motor <NUM>.

It is known that an inverter device which is part of or constituting the power supply device <NUM> is capable of controlling the currents supplied to the electric motor <NUM>, of knowing the instantaneous value of said currents, and of giving continuous information of said instantaneous value of said currents to the electronic control unit <NUM>.

By way of non-exclusive example, a third strategy in the presence of a simultaneous request to supply mechanical torque to the respective compressors <NUM>, <NUM> from the first electrical signal <NUM> and at least one of either the second electrical signal <NUM> or the third electrical signal <NUM>, if the power supply device <NUM> comprises or is constituted of an inverter, provides for the electronic control unit <NUM> to activate simultaneously the first coupling means <NUM> and the second coupling means <NUM>, so as to connect the electric motor <NUM> both to the first compressor <NUM> and to the second compressor <NUM>, as long as the current delivered by the inverter <NUM> does not reach the maximum value that may be supplied by said inverter <NUM>.

When the maximum deliverable current value is reached by the inverter as a consequence of the progressive increase of the pressures downstream of the first and second compressors <NUM>, <NUM>, the electronic control unit <NUM> may subsequently adopt the first strategy or the second strategy described above.

<FIG> illustrates a non-exclusive example of a fixed trainset <NUM> constituted by five cars <NUM>,. , <NUM>, where each car is equipped with a local HVAC system <NUM>,. The train <NUM> is further equipped with two local AGTU systems <NUM>, <NUM>. If the solution of this invention were adopted, the train <NUM> would take the form <NUM> shown in <FIG>, where each car <NUM>,. , <NUM> is provided with its own system for the generation of compressed air and for air conditioning <NUM>,.

In this case, the air flow supplied by the two compressors integrated in the AGTU systems <NUM>, <NUM> is divided between the various systems for the generation of compressed air and for air conditioning <NUM>,.

This new configuration, illustrated in <FIG>, offers the benefit of eliminating the AGTU systems <NUM>, <NUM>, with a consequent reduction in the weight of the train <NUM> and an increase in the space available for the installation of other systems otherwise installed in the car.

Furthermore, the distribution from a limited number of AGTU systems <NUM>, <NUM> to a greater number of systems for the generation of compressed air and for air conditioning <NUM>,. , <NUM> allows the reduction of the flow rate of the compressors integrated in the systems for the generation of compressed air and for air conditioning <NUM>,. , <NUM>, by way of non-exclusive example in the case of <FIG> and <FIG> with a <NUM>:<NUM> ratio. This flow rate reduction makes it possible to switch advantageously, for example, from non-lubricated piston compressors to non-lubricated "scroll" compressors, reducing the acoustic noise generated and the mechanical vibrations induced by the compressors to the relevant cars.

The system described in <FIG> may be equipped with a connection to an on-board communication system <NUM> arranged to connect at least two of the plurality of systems for the generation of compressed air, AGTU, and for air conditioning, HVAC, <NUM>,. , <NUM> aboard said train <NUM>. It should be considered that the main brake pipe <NUM> and the main tank <NUM> are the same for the whole train <NUM> and in common with all systems for the generation of compressed air and for air conditioning <NUM>,.

In this case, the strategy for attributing the drive torque provided by the electric motors <NUM> to the first and second compressors <NUM>, <NUM> of each system for the generation of compressed air and for air conditioning <NUM>,. , <NUM> may be based on a distributed management.

The first among the systems for the generation of compressed air and for air conditioning <NUM>,. , <NUM> which encounters the simultaneous request for mechanical torque to its first and second compressors <NUM>, <NUM> from its electrical signals <NUM> and <NUM>, <NUM>, before prioritizing the request coming from the first electrical signal <NUM>, as previously described in the first, second and third strategy, verifies, by exchanging information through the communication means <NUM>, that at least one other system for the generation of compressed air and for air conditioning <NUM>,. , <NUM> has requested mechanical torque to its second compressor <NUM> from at least one of either its second electrical signal <NUM> or third electrical signal <NUM>. In this case, the first system for the generation of compressed air and for air conditioning will prioritize the request for mechanical torque to its first compressor <NUM> from at least one of its first electrical signal <NUM> or its second electrical signal <NUM>.

In the presence of communication means <NUM> that allows the electronic control units <NUM> of the two or more systems for the generation of compressed air and for air conditioning <NUM>,. , <NUM> to communicate with each other, other distributed strategies may be achieved, similar to the strategies described above, always globally prioritizing the request to supply the main tank <NUM> when the pressure value inside it has reached the minimum value.

Claim 1:
System (<NUM>) for the generation of compressed air and for air conditioning, for at least one railway vehicle (<NUM>, ..., <NUM>), wherein said system (<NUM>) comprises a first compressor (<NUM>) arranged to generate compressed air to supply a main tank (<NUM>) and a main brake pipe (<NUM>) of the railway vehicle through an air drying unit (<NUM>) and a second compressor (<NUM>) arranged to compress a refrigerant gas for an air conditioning system (<NUM>) of the at least one railway vehicle;
the system (<NUM>) being characterized in that it comprises a single electric motor (<NUM>) arranged to generate a mechanical torque adapted to be selectively provided to the first compressor (<NUM>), or to the second compressor (<NUM>), or simultaneously to both the first compressor (<NUM>) and to the second compressor (<NUM>) , as a function of:
- a first electrical signal (<NUM>) generated by a pressure measurement device (<NUM>) and indicative of a pressure present in the main brake pipe (<NUM>), or in the main tank (<NUM>); and
- at least one second electrical signal (<NUM>) coming from the conditioning system (<NUM>) and indicative of a temperature value or a pressure value or a humidity value, and at least a third electrical signal (<NUM>) indicative of a temperature of an environment to be conditioned of the railway vehicle.