1 , at present, the sake of convenience is generally called natural gas vehicles , including CNG, LNG, and LPG vehicles.
CNG (Compressed Natural Gas) vehicles, which is compressed natural gas vehicles .


LNG: liquefied natural gas , such as ( atmospheric pressure -162 ℃) , the load on the low-voltage insulated container in the car , is LNG Liquefied Natural Gas) vehicles, which is liquefied natural gas vehicles .


LPG: NLG part of the recovery and processing of natural gas in the oil refining process , there is a propane and butane gas mainly composed of by-product which is also relatively easy to liquefy , at atmospheric pressure and is gas , liquefied petroleum gas and everyday household is very similar , you can do a motor fuel that is LPG (Liquefied Petroleum Gas), also known as liquefied petroleum gas, LPG ​​cars will also be on the habit as a natural gas vehicle , but some countries, natural gas vehicles excluding LPG vehicles.


2, the gas pressure of the gas in the cylinder is generally 21Mpa (3000psi).


3, the advantages and disadvantages of natural gas vehicles
Advantage
□ ① a higher economic efficiency. In the same heat value equivalent , the world will generally be one cubic meter of natural gas price controls half of one liter of petrol and diesel oil .
□ If all types of engine thermal efficiency is relatively recent , the fuel cost is about half of the natural gas vehicle gasoline or diesel vehicles. Driving a significant reduction in running costs .
□ on automobile engines, natural gas tend to spread , the engine easily and uniformly mixed air , more complete combustion , clean and not prone to carbon deposition , a good anti-knock properties, will not dilute lubricants, thus making parts within the engine cylinder greatly reduced wear , the life of the engine oil and the period of use greatly increased. These will reduce maintenance and operating costs of the car, to improve the economy of car use.
□ ② better social benefits. Compared with the petroleum fuel , the gas fuel is small in energy loss during the preparation , fewer harmful emissions of pollutants to the atmosphere . Consideration from the fuel source , is more favorable to environmental protection .
□ ③ safer. CNG, LNG and LPG cylinders or tanks and other vehicles are very strong and reliable. Natural gas is lighter than air itself (LPG excluded), a slight leak , will soon spread to the atmosphere. Various gas fuel system components , especially the sealing part , are subject to stringent checks. Thus , natural gas as a vehicle fuel is relatively safe .


□ Disadvantages
□ ① Because of the low energy density of the gaseous fuel , a relatively small amount of fuel carried in natural gas vehicles , ships traveling distance shorter than gasoline . Due to occupy a certain volume of gas fuel in the cylinder of the combustible mixture in ( fluid cylinder gasoline engine fuel volume share is negligible ) , in the same cylinder working volume , while using less natural gas as fuel for power . At present, natural gas engines used mostly by the original gasoline engine modification , and thus gasoline vehicles after switching to natural gas power tends to drop about 10% to 20 %, which is the driver said climbing boring, slow response acceleration phenomenon . If diesel vehicles generally use " dual fuel " mode conversion fueled with natural gas , this phenomenon does not occur , but the structure is more complex modification parts .
□ ② Due to the current natural gas vehicles is based on the original gasoline or diesel vehicles on the modification of the original gasoline or diesel fuel system is mostly reserved. Thus, to increase the original automobile fuel gas system, in particular the cylinder so that the original effective reduction of an automobile , but also increases the weight of itself .
□ ③ Natural gas is a gaseous fuel , is not easy to store and carry.
□ Although there are more deficiencies , but the overall economic and social analysis, using natural gas as a vehicle fuel is still more advantages than disadvantages .