DE102008033696B4 - Multi-circuit protection valve for a compressed air supply system - Google Patents

Abstract

Compressed air supply system (32) of a vehicle with a control device (92) and a multi-circuit protection valve (94), - the multi-circuit protection valve (94) being a first check valve (18) arranged parallel to an overflow valve (14; 16) protecting a service brake circuit (10; 12) and - a second check valve (26) arranged in a pneumatic connecting line (20) between a parking brake and trailer supply circuit (22, 22 ') and a supply line (24) of the service brake circuit (10; 12), and - wherein the pneumatic connecting line ( 20) is coupled to a node (28) downstream of a third check valve (30) securing the parking brake circuit (22) against the trailer supply circuit (22 '), characterized in that a relay valve (36) for opening the parking brake via a control line (38 ) from a service brake circuit (10, 12) and via a further control line (38 ') from the parking brake circuit s (22) can be acted upon by control pressures, a solenoid valve (98) which can be actuated by the control device (92) being provided in the further control line (38 ') in order to prevent the parking brake from being actuated.

Description

The invention relates to a compressed air supply system of a vehicle having a control device and a multi-circuit protection valve, wherein the multi-circuit protection valve comprises a first check valve arranged parallel to a service brake circuit protecting a service brake circuit and a second check valve arranged in a pneumatic connection line between a parking brake and trailer supply circuit and a service line of the service brake circuit, and wherein the pneumatic connection line is coupled to a node downstream of a third check valve protecting the parking brake circuit against the trailer supply circuit.

The invention further relates to a method for operating a compressed air supply system of a vehicle having a control device and a multi-circuit protection valve, wherein the multi-circuit protection valve arranged in parallel to a service brake circuit overflow safeguard overflow valve arranged first check valve and in a pneumatic connecting line between a parking brake and trailer supply circuit and a supply line of the service brake circuit arranged second check valve, and wherein at a pressure drop in the coupled by the first check valve to the supply line service brake circuit by a leakage of compressed air from the parking brake circuit via the downstream of the third check valve with the parking brake circuit coupled connection line flows into the supply line, and wherein the compressed air in the leaked service brake circuit flows over and escapes from there.

Commercial vehicles are often equipped with compressed air systems to supply a pneumatic brake system and other compressed air consumers with compressed air. Such compressed air supply systems comprise a multi-circuit protection valve, which serves in particular to protect the individual compressed air circuits against each other and to ensure a certain filling order at commissioning of the motor vehicle. The multi-circuit protection valve assumes a central role with regard to the operational safety of the commercial vehicle. An important aspect of this operational safety is related to the measures in the event of a defect in one of the service brake circuits. Decreases in such a defect, the pressure in the service brake circuits, it must be ensured in terms of a restart of the vehicle after a certain life that the parking brake can not be solved as long as at least the auxiliary brake pressure of the service brake circuits is reached. On the other hand, in the event of a defect, the pressure loss in the parking brake circuit must not be so rapid that an automatic engagement of the parking brake occurs during the drive. This object is generally achieved by a throttled outflow of compressed air from the circuit of the parking brake, wherein the throttle is designed so that the pressure loss in the parking brake through the throttle is not greater than the capacity of the compressor at idle.

It is known to provide for the outflow of compressed air from a common supply circuit of trailer and parking brake a connection channel with a check valve, so that compressed air from the common supply circuit of trailer and parking brake can flow into a circle of the service brake when the pressure in the circuit of the service brake lower than in the common supply circuit of trailer and parking brake. Conversely, the typically higher pressure from the circuit of the service brake from about 10 to 12.5 bar in the direction of the common circle of trailer and parking brake with a maximum of 8.5 bar locked.

It is also known to provide, within a multi-circuit protection valve, a communication passage between a common trailer-parking brake circuit and a common service port of two service brake circuits via a check valve so that compressed air from the trailer and parking brake common circuit can flow back into this supply passage when the service circuit Pressure in the supply channel is lower than in the common supply circuit of trailer and parking brake. Conversely, the typically higher pressure in the supply channel of about 10 to 12.5 bar towards the common supply circuit of trailer and parking brake of a maximum of 8.5 bar is blocked by the check valve. Furthermore, another check valve is to be provided as a bypass parallel to one of the two overflow valves, each of which secures one of the two service brake circuits. Now has the service brake circuit with the check valve as a bypass defect and is depressurized, is vented through the bypass and the common supply channel of the two service brake circuits and the connection channel and the common supply circuit of trailer and parking brake.

The possibilities hitherto known from the prior art cause great complexity in the integration into a single module, in particular with regard to the channel guidance in the housing. This increases the risk of leaks in seals to the outside or from a pressure chamber of the module to a neighboring room of the module, which causes malfunctions.

The DE 10 2005 040 498 A1 describes a multi-circuit protection valve for a compressed air brake system of a commercial vehicle and from the DE 10 2006 023 728 A is a compressed air supply system for a commercial vehicle known.

Furthermore, from the EP 0 642 962 A2 a multi-circuit protection valve with a pneumatic connecting line between a parking brake circuit and a service brake circuit, wherein in the connecting line a check valve is arranged in series with a throttle.

In addition, the shows DE 10 2006 034 785 A1 a compressed air supply system in which the filling of a parking brake and trailer supply circuit via a controllable by a control unit auxiliary consumer pilot valve can be prevented, which can lock a spill valve in the supply line of the parking brake and trailer supply circuit. It is envisaged that the secondary consumer pilot valve is energized immediately after switching on the ignition to realize a "Northland parking brake function".

The object of the present invention is to improve vehicle behavior, in particular with regard to safety aspects.

This object is achieved with the features of the independent claims.

Advantageous embodiments of the invention are indicated in the dependent claims.

The invention is based on the generic compressed air supply system in that a relay valve for opening the parking brake via a control line of a service brake circuit and a further control line from the parking brake circuit can be acted upon with control pressures, wherein an actuatable by the control unit solenoid valve is provided in the further control line, to prevent actuation of the parking brake. The legal requirements regarding the behavior of the parking brake can still be met. At the same time allows the connection point of the pneumatic connection line to different arrangements of the components of the multi-circuit protection valve to each other. The possible arrangements of the components of the multi-circuit protection valve and the associated piping allow further optimization with regard to the number and size of the required sealing surfaces. Thus, the risk of leakage can be achieved by reducing the number of seals and the sealing surface size.

In this context, it is advantageous that the connecting line and the third check valve are completely integrated in the multi-circuit protection valve. This allows a reduction of the pressurized areas.

It is particularly preferred that a secondary consumer pilot valve is provided, via which a filling of the parking brake and trailer supply circuit can be prevented. About the auxiliary consumer / pilot valve, a so-called "northland parkbrake function" is feasible, which is statutory provision in some countries.

Usefully, it can be provided that a throttle is arranged in series with the first check valve in order to avoid a spontaneous pressure drop in the supply line of the service brake circuits in the event of a pressure loss in the service brake circuit downstream of the throttle. By providing the throttle in series with the first check valve, a subsequent delivery of compressed air is made possible in the non-defective service brake circuit and at the same time allows any necessary pressure release from the parking brake circuit.

Advantageously, it is provided that a throttle device is arranged serially to the second check valve in the connecting line in order to avoid an uncontrolled closing of the parking brake at a pressure drop in the supply line of the service brake circuits. By the throttle device in the connecting line is maintained at a pressure drop in the supply line to the back pressure of the throttle device higher pressure in the parking brake circuit. By a suitable dimensioning of the throttle effect of the throttle device thus a sufficient pressure level can be maintained in the parking brake circuit to prevent uncontrolled closing of the parking brake.

The generic method is further developed in that a relay valve to open the parking brake via a control line from a service brake circuit and a further control line from the parking brake circuit is subjected to control pressures, wherein a solenoid valve is provided in the further control line to actuate the parking brake by the Lock the solenoid valve to prevent. In this way, the advantages and particularities of the multi-circuit protection valve according to the invention are also implemented in the context of a method.

This is usefully further developed by the fact that over the connecting line Air volume escaping from the parking brake circuit per unit of time prevents sufficient pressure build-up to actuate the parking brake during a parking phase or an initial filling phase of the initially pressureless compressed air system of the vehicle. Due to the pressure reduction via the connecting line, a parking brake circuit which is vented in the parked state is ensured when the service brake circuit is depressurized.

Furthermore, it can be provided that the air volume escaping via the connecting line from the parking brake circuit per unit time is at most equal to a volume of air supplied to the parking brake circuit per unit time over the multi-circuit protection valve in order to still ensure a sufficient minimum pressure for actuating the parking brake when the pressure drop in the parking brake Service brake circuit occurs after an initial filling phase of the compressed air system of the vehicle.

The invention will now be described by way of example with reference to the accompanying drawing with reference to a preferred embodiment.

Show it:

1 a not claimed first embodiment of a compressed air supply device with integrated multi-circuit protection valve; and

2 a second embodiment of a compressed air supply system with a multi-circuit protection valve.

In the following drawings, like reference characters designate like or similar parts.

1 shows a not claimed first embodiment of a compressed air supply device with integrated multi-circuit protection valve. The illustrated compressed air supply device 32 is, as indicated by the dotted line, integrated into a common, not shown housing. Inside the compressed air supply device 32 arranged pneumatic lines are shown as solid lines, pneumatic control lines are shown as dashed lines and electrical lines are shown as long-dashed lines. The illustrated compressed air supply device 32 includes in addition to an electronic control unit 92 electrically controllable solenoid valves 46 . 48 and 34 , a pneumatically controllable drain valve 58 , a throttle 52 , Check valves 50 and 54 as well as an air dryer 56 , In addition, there are pressure sensors 66 . 66 ' . 66 '' . 66 ''' and a multi-circuit protection valve 94 as an integral part of the compressed air supply device 32 with pressure relief valves 88 . 90 , Overflow valves 14 . 16 . 72 . 76 . 78 and 80 and other components shown. The compressed air supply device 32 can via a compressed air input 40 or a forced ventilation input 42 be supplied with compressed air. The compressed air supply device 32 supplied compressed air is first in the air dryer 56 prepared, that is in particular cleaned of oil and dirt particles as well as air humidity. The thus prepared compressed air is via the check valve 54 a supply line 24 in the multi-circuit protection valve 94 fed. To the supply line 94 are two overflow valves in parallel 14 . 16 connected via the two service brake circuits 10 . 12 be filled with compressed air. Furthermore, it is parallel to the two service brake circuits 10 . 12 an air suspension 74 behind the overflow valve 72 to the supply line 24 coupled. Downstream of the overflow valves 14 . 16 is a shuttle valve 68 connected via the downstream of pressure limiters 88 . 90 and overflow valves 76 . 78 and 80 a parking brake circuit 22 , a trailer supply circle 22 ' , a pneumatic transmission 82 and additional consumers 84 be supplied with compressed air. Furthermore, via the shuttle valve 68 the for a regeneration process of the air dryer 56 necessary regeneration and control air responsible for this solenoid valves 46 and 48 be supplied. Will a regeneration phase of the controller 92 initiated, then the regeneration valve 48 converted into its switching position, not shown, and at the same time or in a short time interval, the drain control valve 46 converted into its switching state, not shown. By transferring the drain control valve 46 in its switching state, not shown, a compressor control input 44 vented so that an unillustrated compressor is transferred to its idling phase, and the drain valve 58 brought into its switching state, not shown. This allows the regeneration required air from the two service brake circuits 10 . 12 over the shuttle valve 68 and the drain valve 48 through the check valve 50 over the throttle 52 , that is bypassing the check valve 54 , through the air dryer 56 and the drain valve 58 to a vent 60 flow, where it leaves the compressed air system. The regeneration air takes in the air dryer 56 Stored oil and dirt particles and moisture on and removes them from the system. After completion of the regeneration phase, the drain control valve 46 and the regeneration valve 48 again transferred to their illustrated switching states. This will cause the compressor control output 44 and the pneumatic control input of the drain valve 58 with a vent 62 coupled and the drain valve 58 again transferred to its illustrated switching state and the compressor, not shown switched back to a funding phase. From the electronic control unit 92 is also the secondary consumer pilot valve 34 switched, which is designed as a 3/2-way solenoid valve. In the in 1 shown switching position connects the auxiliary consumer pilot valve 34 a control input of the overflow valve 76 with the vent 62 , In the not in 1 shown switching position connects the auxiliary consumer pilot valve 34 the control input of the overflow valve 76 with the area downstream of the shuttle valve 86 from which several separate consumer circuits are also supplied, whereby the prevailing pressure in this area to the control input of the overflow valve 76 is created and this overflow valve 76 then the parking brake circuit 22 and the trailer supply circle 22 ' excludes from aftercare. Immediately after switching on the ignition, the secondary consumer pilot valve 34 energized, so that the control input of the overflow valve 76 Compressed air is supplied. This is to prevent prematurely released handbrake in a state in which not enough pressure is built, the vehicle is first braked by the parking brake and in the course of pressure build-up, if the driver may not be in the driver's seat, the vehicle independently starts to roll. Only if via the secondary consumer pilot valve 34 the control input of the overflow valve 76 is vented again, the parking brake can be solved in the usual way. However, this is after reaching a pressure sufficient to the brake system on the service brake circuits 10 . 12 to be able to operate, an actuating signal required by the driver. This operation of the parking brake is called "northland parkbrake function". Inside the multi-circuit protection valve 94 and downstream of the spill valve 76 a branch of the common supply circuit of the trailer and the parking brake is provided. This is the parking brake circuit 22 through a third check valve 30 additionally against a pressure loss in the trailer supply circuit 22 ' hedged. A part of the parking brake module, in particular a relay valve 36 with a vent 64 for actuating spring brake cylinders 86 . 86 ' is structurally in the compressed air supply device 32 integrated. Via redundant pneumatic control lines 38 . 38 ' becomes one downstream of a shuttle valve 70 lying pneumatic control input 36 ' the relay valve, a control pressure supplied, on the basis of the spring brake cylinder 86 . 86 ' via the relay valve 36 with pressure from the parking brake circuit 22 be charged. The pneumatic control lines 38 . 38 ' are part of the parking brake module and are supplied by control valves, not shown, of the parking brake module with a control pressure. The pressure supply to a non-integrated part of the parking brake module, which may include the control valves, may, for example, via the connection of the parking brake circuit 22 respectively. From this then lead the pneumatic control lines 38 . 38 ' back to the compressed air treatment plant 32 , The following is the operation of the described compressed air supply device 32 briefly explained.

First of all, there will be unpressurized service brake circuits 10 . 12 assumed, as occurs after some time in the parked vehicle usually. Is the service brake circuit 12 depressurized, so can over the parallel to the overflow valve 16 arranged serial circuit of a first check valve 18 and a throttle 18 ' also the pressure in the supply line 24 be reduced. As a result, via a second check valve 26 and a throttle device 26 ' which are in a pneumatic connecting line 20 are arranged and to a node 28 downstream of the third check valve 30 coupled pressure from the Festestellbremskreis 22 be reduced. One in the parking brake circuit 22 any existing reservoir is emptied in this way. Thus, a ventilation of the spring brake cylinder 86 . 86 ' via the relay valve 36 not possible. After commissioning the vehicle, the various supply circuits of the multi-circuit protection valve are filled 94 in a sequential manner, in particular the parking brake circuit 22 opposite the service brake circuits 10 . 12 after-care is provided. Therefore, the ventilation of the parking brake cylinder 86 . 86 ' only after reaching the necessary auxiliary brake pressure, whereby the legal requirement is met.

If the vehicle already drives, that is, the individual supply circuits of the compressed air supply device 32 are already filled and the spring brake cylinder 86 . 86 ' over the parking brake circuit 22 ventilated, if a defect in one of the service brake circuits 10 . 12 occurs, an uncontrolled closing the parking brake can be prevented. Occurs, for example, in the service brake circuit 12 a pressure drop due to a defect, so the pressure drop across the parallel to the spill valve 16 arranged bypass from the first check valve 18 and the throttle 18 ' a pressure drop in the supply line 24 cause. Via the pneumatic connection line 20 can be compressed air from the parking brake circuit 22 nachström, which is a pressure drop in the parking brake circuit 22 entails. Due to the throttle device 26 ' in the pneumatic connection line 20 turns in the parking brake circuit 22 one opposite the supply line 24 to the back pressure of the throttle device 26 ' increased pressure level. The opening pressure of the overflow valve 16 should be big enough the necessary switching pressure to open the spring brake cylinder 86 . 86 ' be elected. Typical values for the opening pressure of the overflow valve 16 be at a necessary to actuate the spring brake cylinder switching pressure of 5.5 bar, about 7 bar. Due to the throttle 18 ' in the bypass to the overflow valve 16 the pressure reduction takes place in the supply line 24 sufficiently slow, so that the nachgeförderte by the compressor, not shown compressed air sufficient for safe operation of the compressed air supply device 32 despite a defect in the service brake circuit 12 is. In particular, the supply of the service brake circuit 10 and the subsequent supply of the parking brake circuit 22 be ensured by the nachgeförderte by the compressor compressed air.

2 shows a second embodiment of a compressed air supply system with a multi-circuit protection valve. The illustrated compressed air supply system 32 includes one already from the 1 known multi-circuit protection valve 94 however, does implement the "northland parkbrake function" in an alternative way. The from the 1 already known pneumatic control lines 38 and 38 ' be applied in this embodiment with a control pressure from the service brake or the parking brake. The actuation of the service brake therefore automatically has a pressurization of the valve device 36 through the pneumatic control line 38 result. If the parking brake is closed, that is, the parking brake assigned areas of the spring brake cylinders are depressurized, so pressure is simultaneously built up in the spring brake cylinder to open the parking brake and to close the service brake. This protects the spring brake cylinder against overloading. If the driver wants to open the parking brake, then the pneumatic control line 38 ' subjected to a corresponding control pressure, wherein opening the parking brake by pressurizing the relay valve 36 only possible if there is a solenoid valve 98 is in the illustrated switching position. Is the solenoid valve located? 98 in the switching position, not shown, it is not possible to open the parking brake even with a corresponding driver's request. The solenoid valve 98 can from the controller 92 be operated in response to available pressure levels or a driver presence control, whereby the "northland parkbrake function" can be realized. In the illustrated compressed air supply device 32 is the vent 64 explicitly shown as a silencer. Furthermore, a check valve 96 in the transmission supply connection 82 arranged. Additional check valves to protect individual consumer circuits can be provided as needed.

The features of the invention disclosed in the foregoing description, in the drawings and in the claims may be essential to the realization of the invention both individually and in any combination.

LIST OF REFERENCE NUMBERS

10

Service brake circuit

12

Service brake circuit

14

overflow

16

overflow

18

first check valve

18 '

throttle

20

pneumatic connection line

22

Parking brake circuit

22 '

Trailer supply circuit

24

supply line

26

second check valve

26 '

throttling device

28

junction

30

third check valve

32

Compressed air supply system

34

In addition to consumer-pilot valve

36

valve means

36 '

pneumatic control input

38

pneumatic control line

38 '

pneumatic control line

40

Compressed air inlet

42

Forced ventilation input

44

Compressor control output

46

Drain control valve

48

regeneration valve

50

check valve

52

throttle

54

check valve

56

air dryer

58

drain valve

60

vent

62

vent

64

vent

66

pressure sensor

66 '

pressure sensor

66 ''

pressure sensor

66 '' '

pressure sensor

68

shuttle valve

70

shuttle valve

72

overflow

74

air suspension

76

overflow

78

overflow

80

overflow

82

transmission

84

additional consumer

86

Spring brake cylinder

86 '

Spring brake cylinder

88

pressure limiter

90

pressure limiter

92

control unit

94

Multi-circuit protection valve

96

check valve

98

magnetic valve

Claims (7)

Compressed air supply system ( 32 ) of a vehicle with a control unit ( 92 ) and a multi-circuit protection valve ( 94 ), - the multi-circuit protection valve ( 94 ) a parallel to a service brake circuit ( 10 ; 12 ) ensuring overflow valve ( 14 ; 16 ) arranged first check valve ( 18 ) and - in a pneumatic connecting line ( 20 ) between a parking brake and trailer supply circuit ( 22 . 22 ' ) and a supply line ( 24 ) of the service brake circuit ( 10 ; 12 ) arranged second check valve ( 26 ), and - wherein the pneumatic connecting line ( 20 ) to a node ( 28 ) downstream of a parking brake circuit ( 22 ) against the trailer supply circle ( 22 ' ) securing third check valve ( 30 ), characterized in that a relay valve ( 36 ) for opening the parking brake via a control line ( 38 ) of a service brake circuit ( 10 . 12 ) and via another control line ( 38 ' ) from the parking brake circuit ( 22 ) can be acted upon with control pressures, wherein one of the control unit ( 92 ) actuated solenoid valve ( 98 ) in the further control line ( 38 ' ) is provided to prevent actuation of the parking brake. Compressed air supply system ( 32 ) according to claim 1, characterized in that the connecting line ( 20 ) and the third check valve ( 30 ) completely into the multi-circuit protection valve ( 94 ) are integrated. Compressed air supply system ( 32 ) according to claim 1 or 2, characterized in that in series with the first check valve ( 18 ) a throttle ( 18 ' ) is arranged to at a pressure loss in the throttle ( 18 ' ) Subordinate service brake circuit ( 10 ; 12 ) a spontaneous pressure drop in the supply line ( 24 ) of service brake circuits ( 10 . 12 ) to avoid. Compressed air supply system ( 32 ) according to one of the preceding claims, characterized in that a throttle device ( 26 ' ) in series with the second check valve ( 26 ) in the connection line ( 20 ) is arranged to at a pressure drop in the supply line ( 24 ) of service brake circuits ( 10 . 12 ) to avoid uncontrolled closing of the parking brake. Method for operating a compressed air supply system ( 32 ) of a vehicle with a control unit ( 92 ) and a multi-circuit protection valve ( 94 ), - the multi-circuit protection valve ( 94 ) one parallel to one a service brake circuit ( 10 ; 12 ) ensuring overflow valve ( 14 ; 16 ) arranged first check valve ( 18 ) and one in a pneumatic connecting line ( 20 ) between a parking brake and trailer supply circuit ( 22 . 22 ' ) and a supply line ( 24 ) of the service brake circuit ( 10 ; 12 ) arranged second check valve ( 26 ), and - wherein at a pressure drop in the through the first check valve ( 18 ) with the supply line ( 24 ) coupled service brake circuit ( 10 ; 12 ) by a leakage compressed air from the parking brake circuit ( 22 ) across the downstream of the third check valve ( 30 ) with the parking brake circuit ( 22 ) coupled connection line ( 20 ) into the supply line ( 24 ), and - wherein the compressed air in the leaking service brake circuit ( 10 ; 12 ) flows over and escapes from there, characterized in that a relay valve ( 36 ) for opening the parking brake via a control line ( 38 ) of a service brake circuit ( 10 . 12 ) and via another control line ( 38 ' ) from the parking brake circuit ( 22 ) is subjected to control pressures, wherein a solenoid valve ( 98 ) in the further control line ( 38 ' ) is provided to actuate the parking brake by the locking of the solenoid valve ( 98 ) to prevent. A method according to claim 5, characterized in that via the connecting line ( 20 ) from the parking brake circuit ( 22 ) Air volume escaping per unit of time prevents sufficient pressure build-up for actuating the parking brake during a parking phase or an initial filling phase of the initially pressureless compressed air system of the vehicle. A method according to claim 5 or 6, characterized in that via the connecting line ( 20 ) from the parking brake circuit ( 22 ) per unit of time escaping air volume is at most as large as an over the multi-circuit protection valve the parking brake circuit per unit time supplied air volume to still ensure a sufficient minimum pressure for actuating the parking brake when the pressure drop occurs in the service brake circuit after an initial Befüllphase the compressed air system of the vehicle.

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