Answer :
Final answer:
The tractor protection valve, a safety component in air brake systems of large vehicles, closes automatically to avoid air loss when pressure drops below the manufacturer's specified range, typically between 20 to 45 psi.
Explanation:
The tractor protection valve is a critical safety component in the air brake systems of trailers and heavy-duty vehicles. It is designed to close automatically when the air pressure falls below a certain level to prevent air loss in the tractor and maintain the ability for the driver to control the vehicle. Although the specific pressure range can vary by manufacturer, it typically closes in the pressure range of 20 to 45 psi (pounds per square inch).
When the input cylinder is engaged and pushed downwards in an air brake system, it affects the flow of air in the braking system, similar to how pushing down on a syringe plunger forces fluid out. Conversely, pulling the input cylinder upwards draws air (or fluid in the case of hydraulic systems) back into the system, preventing movement in the other parts connected to the system, akin to drawing fluid back into a syringe.
Systems such as power brakes and those in large machinery like bulldozers may utilize motorized pumps to manage fluid or air pressure. As with maintaining optimal tire pressure for safe and efficient car performance, proper pressure in brake systems is also crucial for safety and operational effectiveness.
