Natural gas powers roughly 15.2 million vehicles worldwide. Natural gas vehicles (NGVs) are good choices for high-mileage, centrally fueled fleets. In many cases, CNG can provide an adequate range for the required vehicle application. The advantages of natural gas as a transportation fuel include its domestic availability, widespread distribution infrastructure, and reduced greenhouse gas emissions compared to conventional gasoline and diesel fuels.
There are mainly three types of NGVs:
Dedicated: These vehicles are designed to run only on natural gas.
Bi-fuel: These vehicles have two separate fueling systems that enable them to run on either natural gas or gasoline.
Dual-fuel: These vehicles have fuel systems that run on natural gas but use diesel fuel for ignition assistance. This configuration is traditionally limited to heavy-duty vehicles.
Light-duty vehicles are typically equipped with dedicated or bi-fuel systems, while heavy-duty vehicles use dedicated or dual-fuel systems. CNG vehicles store natural gas in tanks where it remains in the gaseous state.
High-pressure cylinders used in automobiles are usually divided into 5 types:
Type 1 Cylinders
Type 1 CNG high-pressure cylinders are all metal tanks made either from aluminum or steel. They are the most affordable and the heaviest of all CNG tanks with lowest fuel capacities.
Type 2 Cylinders
Type 2 tanks are manufactured with a metal liner reinforced by glass or carbon fiber composite wrap around the middle; also referred to as “hoop wrap”. The liner and composite each receive 50% of the stress caused by internal pressurization. These high-pressure cylinders are lighter and carry higher capacities than type 1 CNG cylinders, but cost more.
Type 3 Cylinders
Like Type 2, are manufactured by a metal liner, however, reinforced with a full composite wrap covering the entire tank. The full composite wrap absorbs most of the gas pressure. Type 3 high-pressure cylinders are even lighter and carry higher capacity than Type 2 CNG tanks. Of course, they are also more expensive.
Type 4 Cylinders
Type 4 CNG Tanks are manufactured by a plastic gas-tight liner reinforced by a full composite wrap around the entire tank. The entire strength of the tank is composed of composite reinforcement tape. Type 4 high-pressure cylinders provide higher capacity and are lighter than the Type 3 CNG tanks. However, they are the most expensive of all tank types.
Type 5 Cylinders
Type 5 is different from the other carbon fiber tanks in that it is a liner-less fully glass fiber composite tank. These tanks are lighter and more affordable whose capacity is 16%-20% more than other composite cylinder tanks on the market.
CFRT in High-pressure Cylinders
Continuous fiber-reinforced thermoplastic composites made into TOPOLO T-UD series CFRT tapes can be used mainly in 3 types of these tanks: Type 2, Type 3, and Type 4 tanks. The new material strengthens CNC tanks by means of:
Seamless aluminum liner
Excellent impact tolerance
Great heat tolerance