VEHICLE FOR PASSENGER TRANSPORT WITH A PRESSURE PROTECTION DEVICE

[0001]The invention relates to a vehicle for passenger transport according to the preamble of claim 1.

[0002]According to this, a vehicle for passenger transport is known, having at least one air opening which connects an environment of the vehicle, which has an external pressure, to an interior of the vehicle which has an internal pressure and is provided for accommodating passengers, having at least one pressure protection flap for opening or closing the air opening, and having a pressure protection facility for controlling the at least one pressure protection flap, wherein the pressure protection facility has a measuring apparatus for detecting a pressure differential between the external pressure prevailing at an external pressure connection of the measuring apparatus and the internal pressure prevailing at an internal pressure connection of the measuring apparatus and a pressure evaluation facility for monitoring the pressure differential values supplied by the measuring apparatus, wherein the pressure evaluation facility is designed such that, when the pressure differential reaches a predetermined closing threshold value, it triggers the closing of the at least one pressure protection flap and, when the pressure differential reaches a predetermined opening threshold value, it triggers the opening of the at least one pressure protection flap.

[0003]DE 102 33 517 A1 discloses a ventilation system with a pressure protection system for an interior of a vehicle, wherein the air exchange with the exterior can also be realized when pressure surges or pressure waves occur on the external surface of the vehicle.

[0004]Vehicles that are exposed to high pressure fluctuations, such as rail vehicles entering tunnels, are often equipped with a pressure protection facility in order to improve the pressure comfort in the interior of the vehicle provided for passengers. Such a pressure protection facility typically operates passively and comprises a pressure evaluation unit and various pressure protection flaps, for example on the fresh air and/or exhaust air openings of the rail vehicle.

[0005]The pressure protection facility detects critical pressure events, such as for example a rail vehicle entering a (narrow) tunnel at high speed, and triggers a suitable signal to close the pressure protection flaps and thus the associated air openings. This prevents air from being forced intermittently into the interior due to the temporarily high external pressure prevailing in the environment of the vehicle through the air openings connecting the environment of the vehicle to the interior of the vehicle.

[0006]However, as soon as the critical pressure event is no longer present, for example after leaving a tunnel, the pressure protection flaps must be opened again, in particular in order not to exceed a permissible CO2 concentration in the interior of the vehicle. The opening of the pressure protection flaps is also accomplished with the aid of the pressure protection facility, and namely by suitable monitoring of the pressure differential values supplied by the measuring apparatus for the pressure differential. A control algorithm stored in the pressure evaluation unit evaluates the measured pressure differential values and, once the boundary conditions necessary for opening the pressure protection flaps are present, causes the pressure protection flaps and thus the air openings assigned to them to open.

[0007]With the known pressure protection facility, there is the problem of measuring a sufficient pressure differential between the external and internal pressure when the pressure protection flaps are open in order to trigger the detection of a critical pressure event without negatively influencing the detection of the re-opening of the pressure protection flaps. This results in the pressure protection facility either not triggering at all, triggering too late or triggering too often (for example also when rail vehicles meet on an open track). If the pressure protection facility is optimized so that the detection of the closing of the pressure protection flaps works well, problems often arise when re-opening the pressure protection flaps, so that it often leads to a forced opening of the pressure protection flaps for fresh air openings due to too high CO2 concentration in the interior of the vehicle. This then considerably worsens the pressure comfort in the interior of the vehicle.

[0008]Based on this, the invention is based on the object of developing the vehicle of the type mentioned at the beginning in such a way that critical pressure events can be reproduced more effectively, so that there is a significant reduction in false triggering for the closing the pressure protection flaps without the re-opening of the pressure protection flaps being significantly negatively affected.

[0009]This object is achieved in the vehicle described at the beginning by the characterizing features of claim 1.

[0010]According to this, it is provided according to the invention that the pressure protection facility is designed in such a way that, when the at least one pressure protection flap is open, the pressure differential is formed at the measuring apparatus from the external pressure and a reference internal pressure already provided by a reference apparatus. The reference apparatus simulates the internal pressure behavior of the vehicle when the pressure protection flap is closed.

[0011]As a result, consequently when the pressure protection flap is open, the pressure differential is not formed from the external pressure and the real internal pressure in the interior of the vehicle. Rather, the pressure differential results from the external pressure and a reference internal pressure provided by a reference apparatus. The reference apparatus simulates the internal pressure behavior of the vehicle when the pressure protection flaps are closed. This has the advantage that, compared to the prior art, much higher pressure differentials can be measured at the measuring apparatus when the pressure protection flap is still open. This in turn means that the control algorithm of the pressure evaluation facility can be better adjusted and false detections of critical pressure events can be largely avoided. In addition, the pressure comfort in the interior of the vehicle can be significantly improved compared to the prior art, and namely while maintaining high air quality (low CO₂ concentrations).

[0012]Preferably, the reference apparatus can have an external air connection, which is connected to the environment of the vehicle, for simulating the internal pressure, an air reservoir for simulating the interior of the vehicle and a throttle valve for simulating a leakage of the interior, wherein one side of the air reservoir is connected in terms of flow to the external connection via the throttle valve and the other side of the air reservoir is connected in terms of flow to the internal pressure connection of the measuring apparatus. A key aspect for simulating the pressure conditions in the interior of the vehicle is the simulation of the leakage of the interior. The throttle valve used for this purpose can preferably be adjustable in order to reproduce the leakage of the interior as realistically as possible.

[0013]The throttle valve is preferably designed as a capillary, the effective length and/or effective diameter of which can be adjusted. Changing the effective length of the capillary and thus increasing its flow resistance can thus reproduce different leakage values for the interior of the vehicle.

[0014]A filter can be provided between the throttle valve and the external air connection in order to prevent contamination from the environment of the vehicle.

[0015]Preferably, the capillary is adjustable both in its inner diameter and in its length in order to achieve a desired tightness or to simulate a realistic leakage of the interior of the vehicle. Preferably, an inner diameter of 0.13-0.75 mm with a total length of 2-30 cm is to be selected.

[0016]The use of a capillary for the throttle valve has the advantage that a defined leakage area can be selected to be very small in order to achieve typical so-called “dew values” (pressure tightness) of essentially pressure-tight rail vehicles. It should be noted that the size of the leakage area depends on the size of the air reservoir. This is limited in size by the rather confined space available in a rail vehicle, for example.

[0017]In order to implement the function of re-opening the at least one pressure protection flap, it is preferable not to use the reference apparatus, which is used when the pressure protection flap is open, in order to provide a simulated value for the internal pressure of the vehicle. If the reference apparatus were also used when the pressure protection flap is closed, the problem would be that the internal pressure could no longer be equalized when the pressure protection flap is closed. This would prevent an accurate detection for the re-opening of the pressure protection flap.

[0018]It is therefore preferable that the internal pressure connection of the measuring apparatus is connected to the interior of the vehicle via a switchable solenoid valve and that the pressure evaluation facility is designed in such a way that it opens the solenoid valve when the at least one pressure protection flap is closed, so that the pressure differential is formed at the measuring apparatus from the external pressure and the actual internal pressure in the interior of the vehicle.

[0019]In order to improve the acoustic properties of the pressure protection apparatus, it is advantageous if a sound damper is arranged between the solenoid valve and the interior of the vehicle.

[0020]For the purposes of this description, the term “air opening” refers to any opening that connects an environment of the vehicle to an interior of the vehicle in terms of flow. In this respect, the air opening may, for example, be a fresh air opening through which fresh air is drawn in for an air conditioning system of a vehicle. It is equally possible for the air opening to be an exhaust air opening, via which exhaust air is discharged from the interior of the vehicle to the environment of the vehicle.

[0021]It is preferred that the vehicle is equipped with multiple pressure protection flaps which are each assigned to different air openings of the vehicle and are jointly controlled by the pressure protection facility via a control line. For example, an external pressure measurement can be carried out for the right and left side of the vehicle, wherein each side of the vehicle is equipped with a pressure protection facility of the type described above.

[0022]On the other hand, it is also possible for each air opening to be assigned an individual pressure protection facility.

[0023]The pressure protection facility can be used independently of fresh air and exhaust air systems available on the market and their control algorithms and can therefore fundamentally be used across different vehicle projects where a pressure protection system is required. In particular, the reference facility for simulating the interior pressure consists of only a few components and can be easily maintained. Assembly and disassembly is simple. An efficient increase in pressure comfort is made possible at low cost.

[0024]The external pressure connection of the measuring apparatus on one side of the vehicle can preferably be connected in terms of flow to an external pressure connection of a measuring apparatus on the other side of the vehicle via a connecting line.

[0025]An exemplary embodiment of the invention is explained in more detail below with reference to the drawings, wherein functionally identical components are designated with the same reference characters. In the drawing:

[0026]FIG. 1 shows a schematic circuit diagram of a pressure protection facility for a vehicle and

[0027]FIG. 2 shows a schematic side view of the pressure protection facility of FIG. 1.

[0028]FIG. 1 illustrates a pressure protection facility, wherein a right-hand side of FIG. 1 is assigned to a right-hand side and a left-hand side of FIG. 1 is assigned to a left-hand side of a vehicle for passenger transport. The vehicle may in particular be a rail vehicle, for example a high-speed train. The central element of the pressure protection facility is a pressure evaluation facility 1 which is common to both sides of the vehicle and has the task of detecting critical pressure events, such as those that occur when a high-speed train enters a tunnel to the extent that the external pressure of the vehicle increases abruptly. In order to prevent pressure surges in an interior I of the vehicle, which is provided for accommodating passengers, the pressure evaluation facility 1 controls pressure protection flaps 2. The pressure protection flaps 2 are each assigned to air openings of the vehicle which enable an exchange of air between the environment of the vehicle U and the vehicle interior I. For example, the air openings are fresh air openings, via which fresh air can typically be drawn in for an intended air conditioning system of the vehicle, or exhaust air openings, via which air originating from the interior I can be discharged from the vehicle. All of these air openings must be closed when a critical pressure event occurs.

[0029]In order to detect a critical pressure event, in the present exemplary embodiment the pressure evaluation facility 1 is connected to two measuring apparatuses 3, which can be designed as pressure differential sensors and transmit via signal lines 4 currently measured pressure differential values to the pressure evaluation facility 1 shared by both sides of the vehicle.

[0030]On the open route, the pressure protection flaps 2 are open so that an air conditioning arrangement, which is provided on the vehicle and comprises the air conditioning system, various air conditioning ducts, supply and exhaust fans, can work in normal operation.

[0031]On the open route with the pressure protection flaps 2 fully open, the pressure protection facility operates as follows: on one respective side of the vehicle, the measuring apparatus 3 is connected to the environment U of the vehicle via an external pressure connection 5. A reference apparatus 7, which comprises an air reservoir 8, an adjustable throttle valve 9 and a filter 10, is arranged between an internal pressure connection 6 of the measuring apparatus 3 and the environment U of the vehicle. One side of the air reservoir 8, which simulates the interior I, is connected to the internal pressure connection 6 of the measuring apparatus 3 via lines 11 and 17, while the other side of the air reservoir 8 is connected to the environment U via the throttle valve 9 and the filter 10. The adjustable throttle valve 9 simulates a typical leakage of the interior I, while the filter 10 has the task of keeping impurities originating from the environment U of the vehicle away from the throttle valve 9. The throttle valve 9 is preferably designed as a capillary, the length and/or diameter of which can be adjusted so that it can reproduce very low leakage values, such as those found in modern high-speed trains, which are essentially pressure-tight. As a result, the pressure differential values provided by the measuring apparatus 3 with the pressure protection flaps 2 open are based on the actually prevailing external pressure in the environment U of the vehicle and an internal pressure simulated with the aid of the reference apparatus 7 under the boundary condition that the pressure protection flaps 2 are closed. This allows higher pressure differentials to be measured when the pressure protection flaps 2 are (still) open.

[0032]When entering a tunnel, the pressure differential values measured by the measuring apparatus 3 rise abruptly so that a predefined closing threshold value for the pressure protection flaps 2 is reached. The pressure evaluation facility 1 detects this and triggers the closing of the pressure protection flaps 2 on both sides of the vehicle. With the critical pressure event that is detected in this way, the value which is used in the pressure differential measurement for the internal pressure at the internal pressure connection 6 changes. Solenoid valves 13 assigned to a particular side of the vehicle are opened via an electrical control line 12. These solenoid valves 13 have an interior connection 14 which is assigned to the interior I and is connected in terms of flow to the interior I via a sound damper 15. A connection 16 of the solenoid valves 13 facing away from the interior I is connected both via lines 19 and 11 directly to the air reservoir 8 and via lines 19 and 17 to the internal pressure connection 6 of the measuring apparatus 3. In this respect, when the solenoid valve 13 is open, the pressure actually prevailing in the interior I is present at the interior connection 6, so that the pressure differential value supplied by the measuring apparatus 3 is based on a real external pressure in the environment U of the vehicle and a real internal pressure in the passenger compartment I of the vehicle.

[0033]As the pressure equalization progresses, the values for the pressure differential provided by the measuring apparatus 3 decrease. When a predefined opening threshold value for the pressure differential is reached, the pressure evaluation facility 1 triggers an opening of the pressure protection flap 2 and automatically closes the solenoid valves 13 via the electrical control line 12.

[0034]In a modified embodiment of the invention, the external pressure connection 5 of the measuring apparatus 3 on one side of the vehicle can be connected in terms of flow to the external pressure connection 5 of the measuring apparatus 3 on the other side of the vehicle via a connecting line 18 shown in FIG. 1. Since this compensates for one-sided pressure events (such as a train being encountered on an open track) and therefore no false triggering of the pressure evaluation facility 1 occurs, a measuring apparatus 3 can be omitted or provided as redundant.

[0035]It should be emphasized that, as described in FIG. 1, the pressure evaluation facility 1 can be designed to control multiple pressure protection flaps 2. However, it is also possible that a separate pressure evaluation facility 1 is provided for each individual pressure protection flap, irrespective of which type of air opening between the environment U and the interior I it is assigned to.

[0036]FIG. 2 shows a part of the pressure protection facility explained with reference to FIG. 1 in its spatial configuration. The air reservoir 8, one side of which is connected to the environment U of the vehicle via the throttle valve 9 and the filter 10, is located in a central position. The other side of the air reservoir 8 is connected to the internal pressure connection 6 of the measuring apparatus 3 via the line 11. Furthermore, the latter side of the air reservoir 8 is connected to the solenoid valve 13 in terms of flow, and namely via line 19.

[0037]The design of the throttle valve 9 as a capillary should be emphasized. The internal diameter and length of the capillary 9 are selected depending on the volume of the air reservoir 8 used so that the leakage area per volume corresponds to the behavior of the actual volume of the interior of the vehicle I with the characteristic leakage areas when the pressure protection flaps 2 are closed.