Control unit

1. A brake system ( 1 ) for a commercial vehicle ( 100 ) and an attached trailer, with

a trailer control valve ( 24 ) for activating a trailer brake system from the commercial vehicle ( 100 ),

a supply pressure line ( 46 ) for subjecting the trailer brake system to a supply pressure,

a control pressure line ( 44 ) for subjecting the trailer brake system to a control pressure that is controlled by an operator via an input mechanism,

a valve arrangement formed as a valve unit ( 40 ) for a selective connection of either the supply pressure line ( 46 ) or the control pressure line ( 44 ) to the trailer control valve ( 24 ), and

an electronic control unit ( 10 ) configured to perform electronic brake control and to switch the valve arrangement between

a) a first switching state connecting a trailer-side pressure line ( 52 ) to the control pressure line ( 44 ), and

b) a second switching state connecting the trailer-side pressure line ( 52 ) to the supply pressure line ( 46 ),

wherein the valve arrangement is configured to subject the trailer-side pressure line ( 52 ) to a selectable controlled pressure in a brake control situation in response to a corresponding command from the electronic control unit ( 10 ),

wherein the valve unit ( 40 ) comprises a valve housing with a compressed air port ( 54 ) for discharging venting air, the compressed air port ( 54 ) for discharging the venting air being fluidicly connected to a noise attenuator ( 51 ).

2. The brake system ( 1 ) as claimed in claim 1 ,

wherein the electronic control unit ( 10 ) is configured to switch the valve unit ( 40 ) into

c) a third switching state venting the trailer-side pressure line ( 52 ).

3. The brake system ( 1 ) as claimed in claim 1 ,

wherein the electronic control unit ( 10 ) is configured to switch the valve unit ( 40 ) into

d) a further switching state maintaining the pressure in the trailer-side pressure line ( 52 ).

4. The brake system ( 1 ) as claimed in claim 1 ,

wherein the valve housing comprises a compressed air port for the supply pressure line ( 46 ), and a compressed air port for the trailer-side pressure line ( 52 ).

5. The brake system ( 1 ) as claimed in claim 4 ,

wherein the valve unit ( 40 ) comprises a plurality of switching stages (I, II, III) disposed in the valve housing and a flow path extending along the switching stages (I, II, III).

6. The brake system ( 1 ) as claimed in claim 5 ,

wherein at least one of the switching stages is embodied by a solenoid valve ( 42 a - c ).

7. The brake system ( 1 ) as claimed in claim 1 ,

wherein the valve housing comprises a compressed air port for the control pressure line ( 44 ).

8. The brake system ( 1 ) as claimed in claim 7 ,

wherein a first switching stage (I) is configured to fluidicly connect a flow path selectively either to a compressed air port for the supply pressure line ( 46 ) or to the compressed air port for the control pressure line ( 44 ).

9. The brake system ( 1 ) as claimed in claim 8 ,

wherein a second switching stage (II) is arranged to selectively either open the flow path or close the flow path fluid tight.

10. The brake system ( 1 ) as claimed in claim 9 ,

wherein a third switching stage (III) is configured to connect the flow path selectively either to a compressed air port for the trailer-side pressure line ( 52 ), or to connect the compressed air port for the trailer-side pressure line to the compressed air port ( 54 ) for discharging the venting air.

11. A commercial vehicle ( 100 ) with a trailer, comprising a pneumatic brake system ( 1 ) according to claim 1 .