CNG cylinders are high-pressure containers used to store compressed natural gas. This high-pressure container containing flammable and explosive gas is a pressure container with explosive danger. The gas storage pressure of the vehicle cylinder is 20MPa.

CNG is the English abbreviation of Compressed Natural Gas, the English word for compressed natural gas. Compressed natural gas generally refers to gaseous natural gas (methane as the main component) that can be used as fuel for vehicle engines after multi-stage pressurization to about 20MPa.

CNG cylinders are divided into four categories
The first category is steel or aluminum alloy metal bottles (CNG-1);
The second category is a composite Gas Cylinder (CNG-2) with steel or aluminum lining and a cylinder body reinforced with "hoop winding" resin impregnated long fibers;
The third category is composite gas cylinders (CNG-3) reinforced with steel or aluminum lining and "wound wound" resin impregnated long fibers;
The fourth category is composite gas cylinders (CNG-4) reinforced with plastic linings and "wrapped" resin-impregnated long fibers.
Each of these types of gas cylinders has its own advantages and disadvantages, and can be selected and used according to different models.
At present, steel gas cylinders are mainly used in my country, whose performance must meet the requirements of GB17258 "Compressed Natural Gas Cylinders for Automobiles". Generally, high-quality chromium-molybdenum steel is used as the material of the cylinder.
A complete compressed natural gas cylinder for automobiles should have a bottle cap, a bottle valve and a safety relief device. The bottle cap can protect the bottle valve, and the type of safety relief device on the bottle valve should be a combination of bursting disc and fusible plug.