GB2035487A - Electro-pneumatic rail vehicle braking - Google Patents

Abstract

A rail vehicle brake installation having pneumatic or electro-pneumatically operated brakes comprises at least one programmable microprocessor (23) adapted to be triggered by electrical input control signals produced from a pressure-voltage transducer converting the pressure behaviour of the main air line (HL) into these control signals, to provide output signals to solenoid valves for the air brakes. By changing the programme of the microprocessor common braking components may be used for different applications e.g. a passenger train and a shunting engine. Furthermore, there is provided a plurality of mechanical-electrical (D1-D5, D15, D16, V1, V2) and/or electrical signal transmitters (S1-S3; S3- S8; S6; 29, 30, 34) for detecting for example the vehicle load, the travel velocity, the vehicle retardation, possible non-skid procedures, the emergency brake actuations, the pressure in the pressure air supply and the brake pressure. The electrical signals from which are fed also to the microprocessor which produces therefrom, to correspond to pre-programmed braking functions, output signals for controlling the pneumatic operation of brake cylinders, magnetic-rail braking, sand strewing, brake and release acceleration etc. For safety reasons, there may be provided a plurality of microprocessor systems operating parallel to each other and the output signals of which are compared with each other. <IMAGE>

Description

SPECIFICATION Device for controlling pneumatic or electro-pneumatic brakes on railway vehicles The invention relates to a device for controlling pneumatic or electro-pneumatic brakes on railway vehicles, wherein electrical signals associated with predetermined pressures of the braking installation and generated by pressure-voltage transformers are fed to an electronic signal processing device and are there converted to control signals for solenoid valves for brake actuation.

Such a device is known from German Auslegeschrift No. 22 18 315. In that case, however, the electrical signals are employed additionally to pneumatic control signals, the presetting of brake control signals taking place pneumatically.

In view of the continuously more and more complex braking demands for rail vehicles wherein a plurality of brake functions and dependence of many influencing variables is carried into effect, such as for example blocking protection signals, target braking, automatic travel and brake control (AFB), line-train influencing (LZB), train-type variation (goods-train (G); passengers' train (P); touring train (R)), load-dependent braking, high-speed braking, magnet-rail braking, sanding, brake acceleration, release acceleration, velocity-dependent braking, to mention only a few of them, this known device is very incomplete.

Thus, it is the object of the invention to so improve the device thus indicated that all desired braking functions can be controlled with the aid of electrical signals obtained from the electronic signal processing device.

This problem is solved by the feature indicated in the characterising part of claim 1.

Advantageous embodiments and further developments of the invention are described in the subclaims.

The basic idea of the present invention resides in that the entire signal processing of the vehicle braking installation is electronically effected in a rail-carriage or in another carriage, such as for example a touring train carriage, the correcting functions being pneumatically designed.

At the present day, signal processing is effected purely pneumatically-mechanically or electropneumatically-mechanically, the correcting function being pneumatic-mechanical.

In the case of the present invention, the entire signal behaviour of the hitherto complex pneumatic devices (for example control valve) is simulated to be purely electronic.

By employing programmable microprocessors, the entire necessary signal structure is variable to comply with the particular case of application (for example goods-train, passenger train, railcar) by means of simple programme-technical measures, without it being necessary to make amendments in the hardware or in the other elements of the braking installation.

With this arrangement, then, for example the brake desired and actual values, to the extent that they are not present as electrical signals, are converted to such in mechanical or pneumaticelectrical transducers.

Starting from the guiding variables, the microprocessor then calculates, on the basis of the command structure of the programme in extremely short cycles, the condition of the output signals which is new in each particular instance for the pneumatic correcting elements.

An extremely important advantage of the device according to the invention resides in the considerably reduced costs relative to the known devices, in particular in the case of a comparison of the system costs arising in the known installations due to compressed air apparatus, pipe-laying and installation costs.

Further important advantages of the device according to the invention are inter alia: extremely short dead times, no hysteresis and temperature effects; high flexibility of the signal structure, i.e. in the case of variations of the braking functions of an installation for a predetermined case of application only a programme variation without hardware variation (ready ability for subsequent equipment and small number of apparatus versions) is necessary; -improvement of the control behaviour, for example due to compensation of the frictional value oscillations of the brake linings;; -improvement of the control valve due to supplementary functions such as service brake and release acceleration in each stage, also change-over of multi-release to single-release operation (due to switches) readily possible; -functional testing of all structural elements in condition and during travel due to voluminous test programmes is possible; -in the case of electrical control signals, preset by AFB, radio-telecontrol, EP control, no multiple changing of the mode of signal processing is necessary, whereby a reduction of the structural element outlay is achieved; and --costs-advantageous concept, with increasing complexity of the signal processing increase of the costs advantage.

Further invention-important features and advantages of the invention can be gathered from the following description in which the invention is described in greater detail with reference to examples of embodiment and in combination with the figures, in which: Figure 1 shows an example of embodiment of the invention in the case of employment in a touring train carriage; Figure 2 shows a further example of embodiment of the invention on employment in a section switch engine; Figure 3 shows a further example of embodiment of the invention on employment in a direct electro-pneumatic brake, such as is employed for example on underground railways or tra mways.

In the individual figures, like elements have been given the same reference numerals.

In Fig. 1 there is shown the braking installation of a touring train car the purely pneumatic element of which comprises substantially the following details which, as described hereinbelow, are connected with each other: A main air line HL, a main container line HB, a supply air container R with attached supply air container line 10 connected via a cut-out cock (brake) 11 on the one hand via a non-return valve 12 with the main container line HB and on the other hand via a two-point solenoid valve 15 bridged by a nozzle 14 and a further non-return valve 13 with the main air line HL. The passage direction of the non-return valves 12 and 1 3 is characterised by the arrows shown in the figure.The supply air container R is, via a portion of the line 10 into which a maximum pressure limiter 1 6 is inserted, connected with a bogey equipment 1 7 comprising for example two brake cylinders designed as spring storage cylinders F and adapted to be connected via separate three-point solenoid valves 18 with the line 10. Furthermore, via a two-point solenoid valve 19 an actuating cylinder 20 for a magnetic rail brake is adapted to be connected with the line 10. The lines HL and HB are equipped in known manner with shut-off valves and couplings for connection with further vehicles.The lines HL and HB are furthermore connectable with each other via a two-point solenoid valve 21 for release acceleration and the line HL is connectable to the high-speed braking (emergency braking) system via a two-point solenoid valve 22 having atmospheric pressure.

Connected to the main air line HL is a first pressure transmitter D1, to the supply air container line 10 a second pressure transmitter D2 and between the three-point solenoid valves 1 8 and the spring storage cylinders F third and fourth pressure transmitters D3 and D4 are connected to the lines connecting these elements. Furthermore, a fifth pressure transmitter D5 is connected to a line carrying the air-spring pressure if load-dependent braking is provided.

The pressure transmitters D1-D5 convert the measured pressure of the corresponding line into corresponding electrical signals E1-E5.

Furthermore, in the present example of embodiment, there are provided two velocity transmitters V1 and V2 supplying corresponding electrical signals E6 and E7 to the vehicle or wheel-rotation velocity of individual axles or wheels of the vehicle. Finally, there are also a switch S1 for the handbrake, a switch S2 for the emergency brake and a switch S3 for traintype changing (G, P, R), which supply electrical signals E8, E9 or E10. The signals El to E10 are fed via electrical lines to a first microprocessor system 23 and are there fed to an input board 24 connected with a microprocessor 25.

The microprocessor 25 is, for its part, connected with an output register 26 which in the present example supplies seven output signals Al to A7, which according to the table following hereinbelow are fed to the individual solenoid valves or actuating members.

Al to two-point solenoid valve 22 (high-speed braking) A2 to two-point solenoid valve 1 9 (magnet-rail brake) A3 to corresponding two-point A4 to solenoid valve 18 of the individual axles A5 to a display device 27 (brake condition) A6 to two-point solenoid valve 1 5 (R-filling, cross-section changing) A7 to two-point solenoid valve 21 (release acceleration).

It is clear that the signals E1-E10 and A1-A7 are present in suitable form for triggering the microprocessor system or the individual solenoid valves or actuating means and, where appropriate, corresponding signal preparation devices, such as for example analog-digitaltransducers, frequency and voltage transformers, driver stages, etc. are to be provided.

For reasons of operational reliability, there may be provided also a second microprocessor system only the input lines for this are shown-which is connected in parallel with the microprocessor system 23, corresponding outputs of this second system being for example ORlinked with outputs A1-A7. It may also be expedient to test for correctness the output signals of the two microprocessor systems 23 and 28, by comparison with those of a third microprocessor system (not shown).

In the microprocessor systems 23 and if appropriate 28, correspondingly programmed calculation regulations ... the input signal El-ElO, or some of them with each other, for generating the output signals A1-A7 or one or more of them are linked. The programmed calculation regulations correspond to the desired brake functions.

In the case of the example of embodiment of a touring train carriage according to Fig. 1, the braking value desired values are pneumatically preset in known manner via the pressure of the main air line HL from a driver's braking valve (not shown).

These desired values are converted in the pressure transmitter D1 which for example linearly converts a pressure variation into a voltage variation, to electrical desired values (signal El).

Further desired values are generated via the switches S1-S3 (signals E8-E10). The pressure converters D3 and D4 supply the actual values of the brake cylinder pressure (signals E3, E4), the pressure converter D5 the load actual values (signal E5), the pressure converter D2 the pressure value (signal E2) of the supply air container R and the transmitters (datum sources) V1 and V2 the axle-velocities (signals E6 and E7).

In the microprocessor 25, the signal structure of a control apparatus (for example the control apparatus of the Appiicants having the type designation KES) is simulated, i.e. the connections of HL, C, R and A-pressure are represented to correspond to the UIC Regulations (C-pressure is the brake cylinder pressure and A-pressure is the control pressure of the KE control valve of the Applicants). The pressure variations of HL, C and R are measured directly (signals El, E2, E3 and E4) whereas the A-pressure is electronically formed.

Out of the input signals, the output signals for the solenoid valve 18, which regulate-in the braking cylinder pressure, are calculated. Similarly, in the event of high-speed braking the solenoid valve 22, operating as "high-speed brake accelerator", is triggered and the main air line pressure is reduced in aimed fashion.

The solenoid valve 22 operates also as accelerator for the first stage of the service braking. A cross-section change in connection with the filling of the supply air container R is effected with the nozzle 14 and the solenoid valve 1 5.

The functions "load braking" and "blocking protection" are also calculated out of the input signals and the carrying into effect of the commands of the output signals A1-A7 is carried into effect.

Generally, it is possible with the microprocessor to carry into effect two different control principles. It is possible to regulate to constant brake cylinder pressure corresponding to the preset desired value, the pressure transmitters D2 and D3 or D4 closing the control loops (in this case, the desired value is modifiable via further brake functions such as for example load braking, blocking protection, etc.). Furthermore, there may be effected regulation also to constant vehicle delay (negative acceleration -b) to correspond to the preset desired value.

Therewith, it becomes possible to compensate for friction value fluctuations of the brake linings and section tendencies. The pressure transmitters D3 and D4 are then not entirely necessary, since the control circuit is connected via the velocity datum sources V1 and V2 of the axles.

From the actual value of the acceleration the differentiation of the axle velocities is obtained and compared with the -b- brake desired value in the microprocessor which calculates the control deviation for the solenoid valves (for example 18).

The simulation of the hitherto employed pneumatic control valve by the microprocessor also makes it possible, without difficulty, to improve the behaviour of the braking installation due to supplementary programme commands, in that for example there is associated with each brake stage of the service braking an acceleration (brake and release acceleration). For the release acceleration, in addition to the programme amplification, only the supplementary solenoid valve 21 is necessary, which during a short period of time triggers pressure into the HL line from the HB line.

Fig. 2 shows an example of embodiment of the invention on application thereof to a section switch engine.

The braking installation shown there also has an HL and an HB line, a supply air container R and also spring-storage cylinders F.

Furthermore, the following measurement sensors and correcting elements are provided, which are listed in the following table.

Reference Signal Designation connected witb/or sign Punction D1 El Pressure tíain air line datum source D2 E2 Pressure Main container pres datum source sure line s3 E3 Switch in Brakes driver's brake valve 54 E4 Switch in High-speed braking driver' 5 brake valve s5 E5 Switch in Lutomeic filling im driver's pact brake valve 56 E6 Switch in Release driver's brake velve S7 E7 Switch Shut-off S8 E8 Sensor Equaliser #E9# Radio tele- Brakes ElO c Release 29, 30 ElI ontrol1 Automatic filling surge 12 ) AFB HiEh-speed braking V1 E13 Velocity Axle 1 datum source axle I V2 E14 Velocity Axle 2 datum source axle 2 D15 E15 Pressure da- Spring storage cylin tum source der axle 1 D16 E16 Pressure da- Spring storage cylin tum source der axle 2 21 A1 3-point sole- HL and HB line/RL pres noid valve sure control 22' A2 2-point sole- EL line/hiEh-speed brak noid valve ing, brake acceleration and Sifa braking 18' A3 3-point sole- Brake-cylinder pressure noid valve (C pressure axle 1 A4 3-point sole- Brake-cylinder pressure noid valve (C pressure axle 2

Furthermore, there is also provided a brake lever 31' which is displaceable into the positions braking (BR), high-speed braking (SB), neutral position (0), release (LO) and filling surge (FU) whereby correspondingly the switches S3, S4, S5 or S6 are actuated, which transmit the signals E3-E6.

For direct braking, there is provided a driver's brake valve 32 having a driver's brake lever 31 connected with the HB-line, atmosphere and a Cv input of a relay valve 33. The relay valve 33 is furthermore connected with the supply air container R and with two double feed-back valves 36 each of the other connections of which is connected with the spring-storage cylinders F and the three-point solenoid valves 18'. The latter are also connected with the HB line.

The signals El to E16 are converted analogously to the above-described example of embodiment of Fig. 1 into signals A1-A4.

It should be pointed out that in the case of section locomotives and switch locomotives, due to progressive automation with automatic travel and brake control (AFB) 30, line influencing (LZB) and radio telecontrol 29, the signals E9-E12 are already available in electrical form.

Furthermore, there is provided an EP conditioning 34 (possibly designed to be capable of being subsequently equipped) which supplies signals A3 and A4 as a function of pressures on release or brake lines.

In the event of manual actuation of the automatic brake, the desired values are fed-in via the driver's brake lever 31 having electrical switches (S3-S6) (time-dependent control) into the microprocessor 25. The processor calculates the output values for the pressure variation of the HL line (control of the train brake) and the brake cylinder pressures of the locomotive.

For determining the pressure variation in the HL line, the actual values of the HL pressure are fedback via the pressure datum source (D11 arranged to be redundant for safety reasons-into the microprocessor 25 where the output signal for the three-point solenoid valve 21, the pressure reduction, increase and holding of the HL line is carried into effect. For introduction of high-speed braking operations there serves the two-point solenoid valve 22' which is also guided by the microprocessor 25 which, again to correspond to the braking desired value calculates the brake cylinder pressures in a manner similar to that described hereinabove, in which case control valve, anti-skid means and load braking are simulated.

In the case of automatic guiding of the locomotive over LZB, AFB or radio tele-control, the signals (E9-E12) pass directly into the microprocessor 1 2 which, as in the case of manual operation, supplies the output values for the pressure control of the HL line and the brake cylinder pressures of the locomotive.

The EP control can also be carried into effect in simple manner. The desired values are manually and electrically preset from the driver's brake lever 31, 31' and the microprocessor 25 forms, in the control circuit as previously, the signals for the locomotive and carriage control.

With regard to the functions AFB, EP control or radio tele-control, it should be pointed out that the brake control, the microprocessor system being adequately dimensioned, can be subsequently equipped only due to exchange of storage building blocks (programmable onlyread-store, PROMS) or other variation (exception, cable laying).

The direct brake of the locomotive and of the emergency brake path 35 are pneumatically designed, as hitherto.

Further embodiments are possible for operation of the brake. As replacement for the driver's brake valve 32 in the case of switch locomotives, it will be possible to provide a selector switch with which an optional brake path (within the zone of possible brake paths) for target braking is preset.

A further possibility is the presetting of a velocity reduction within a predetermined time. The control is effected in the microprocessor 25. The problem is, as in the case of anti-skid measures, the detecting of the real train velocity which should not take place via the braked axles. One solution might be a Doppler radar system.

Fig. 3 shows a direct EP brake according to the invention.

The main container line HB is connected via a non-return valve 13, a cut-out cock 11', the supply air container R and in each particular instance a three-point solenoid valve 1 8 with the spring storage cylinders F.

The following metering sensors and actuating means are provided:

Reference Signal Designation connected with/function numeral D1' El' Pressure dat- RB line/RB pressure um source datum source D2' E2' Pressure dat- Brake cylinder axle 1 um source D3' E3' Pressure dat um source Brake cylinder axle 2 V1 B4' Velocity dat- Axle 1 um source axle 1 V2 E5' Velocity dat- Axle 2 um source axle 2 S6' E6' Switch Emergency brake D7' E7' Pressure dat- Air spring E8' um source Brake desired values 18 Al 3-point sole- Brake cylinder 7 noid valve 18 A2 3-point sole- Brake cylinder 2 noid valve 37 A3 2-point sole- Coupling noid valve 38 A4 2-point sole- Coupling noid valve This example of embodiment relates to the equipment of an underground rail car.The brake signals are electrically transmitted into the cars as so-called VOV signals (corresponding to the provisions of the Committee for Public Traffic Operations). The entire pneumatic and electrical hardware necessary for the brake control is illustrated in the form of block circuit diagrams.

The brake value desired values (signal E8') are electrically preset in the car, the decoding takes place in the microprocessor 25, and similarly the emergency brake signal (E6') is introduced. Via the sensors, which supply the actual values of the load (E7'), the axle velocities (E4', E5') and the pressure values for the brake cylinders (E2', E3'), the intermeshed control circuit (multi-loop control system) for the brake cylinder pressure is closed in microprocessor 25 which in predetermined interrogation cycles and within extremely short time (1-3 msec) calculates the brake cylinder pressure required in each particular instance as a function of the brake value desired values and the actual values of wheel velocity (anti-skid function), brake cylinder pressure and load (for each axle), and supplies a correcting signal A1 and A2 to the three-point solenoid valves 1 8. Each optional pressure value can, with an extremely short dead time (10-20 ms) and a high degree of accuracy, be regulated-in at the solenoid valve. The brake cylinder should here again, for safety reasons and due to the simple possibilities for representing the parking brake, be a spring storage cylinder F.

Claims (8)

1. A rail vehicle brake installation having pneumatic or electro-pneumatically operated brakes and comprising: solenoid valves for controlling the supply of pneumatic pressure to operating parts of the brake installation; a plurality of pressure-voltage transducers for generating electrical signals associated with predetermined pressures of the brake installation; and a signal processing device responsive to said electrical signals in order to convert the signals into control signals for the solenoid valves; in which the signal processing device comprises at least one programmable microprocessor arranged to be supplied additionally with a plurality of electrical imput signals from a plurality of electro-mechanical transducers and/or a plurality of electrical signal transmitters, the microprocessor generating in accordance with pre-programmed brake functions a plurality of output signals for controlting said solenoid valves.

2. An installation according to claim 1, in which the pre-programmed braking functions of said microprocessor comprise one or more of the following functions: blocking protection, antiskid, load-dependent braking, high-speed braking, train-type-dependent braking, magnetic rail braking, sand strewing, brake acceleration, release acceleration and staged or stage-less service braking.

3. An installation according to claim 1 or 2, in which the electrical signal processing forms with the signal transmitters and the solenoid valves a control circuit the desired value of which is a constant braking cylinder pressure or a constant vehicle delay.

4. An installation according to any one of claims 1 to 3, in which the braking functions are variable by varying the programming of the microprocessor.

5. An installation according to any one of claims 1 to 4, in which there is provided a second microprocessor system, on breakdown of the first mentioned microprocessor system, performs the function thereof.

6. An installation according to any one of claims 1 to 4, in which there are provided two microprocessor systems which compute the output signals parallel and independently of each other, there taking place, if appropriate, with a third processor system, a comparison of the output data for correctness.

7. An installation according to claim 1 and substantially as hereinbefore described with reference to, and as shown in any one of the embodiments illlustrated in the accompanying drawings.

8. A rail vehicle provided with an installation according to any one of the preceding claims.