| 摘要 |
A brake system for a heavy-duty vehicle includes a service brake system and a park brake system. The park brake system includes a park brake control valve that receives input commands from a vehicle operator and a park brake interlock valve that is in fluid communication with an air supply and the park brake control valve. After the park brakes are moved to an applied position, the park brakes can only be released if a park brake release command is communicated to the park brake control valve and the service brake system is in an applied position. The park brake interlock valve includes an inlet port in fluid communication with a vehicle air supply, an outlet port in fluid communication with the park brake control valve, and a valve assembly for controlling fluid flow between the inlet and outlet ports. When service brakes are applied, the valve assembly allows fluid communication from the inlet port to the outlet port, which pressurizes the park brakes to move the park brakes to the released position.
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