How to refuel the fuel tank for natural gas vehicles?

Hello, the pressure of natural gas vehicle is high. Just drive the vehicle to an open place, then manually open the exhaust valve to achieve the effect of pressure relief, and then fill it up. It should be noted that when designing LNG automobile gas cylinders, a two-stage safety valve is designed considering the pressure rise caused by temperature rise. When the pressure in the bottle exceeds 1.2 times of the normal working pressure, the primary safety valve will exhaust, and the pressure in the bottle will drop accordingly, and it will not stop until the pressure drops to 1.2 times of the working pressure. If the pressure of the primary safety valve does not drop to the normal state after venting, the secondary safety valve will open (1.8 times the working pressure).