Natural gas vehicles (NGV) use compressed natural gas (CNG) rather than liquid natural gas (LNG) such as butane and propane. Because CNG burns cleanly with few emissions, NGVs are popular outside the United States. NGVs haven't been as popular in the U.S. because natural gas isn't as available as gasoline at filling stations, although it is a common fuel for shuttles, buses, and fleets that must meet government clean-air requirements or are looking for a less expensive alternative to gasoline or diesel.
The biggest differences between gasoline vehicles and NGVs are as follows: Because CNG is compressed, it requires fuel tanks that can withstand such pressure. The fuel is measured in units called gasoline-gallon equivalents, or GGE.
Fuel lines on NGVs also have to be high-pressure lines, and the fuel injection delivery system has to be specially made for CNG. But after the gas is mixed with air and injected into the engine's combustion chamber, the engine works the same as a gasoline ICE. A significant difference occurs at the tailpipe, however. CNG produces far fewer pollutants than either gasoline or diesel, which means that most NGVs meet low- to ultra-low emission standards.
There are three levels of NGV technician training required, depending on your job duties. Technicians may need only one—or all three levels—of training. While CNG vehicles are not popular in the Northeast Ohio area yet, we have trained ASE Certified CNG mechanics on staff who can service and or convert these vehicles, and have been trained specifically for the unique challenges that come with these engines.
There are two types of NGV fuel systems and both are unfamiliar to traditional technicians. The key to performing safe, efficient and cost-effective maintenance and repair of natural gas vehicles is adequate training.
Whether you are performing routine maintenance, diagnosing and repairing a problem, or converting a vehicle to run on CNG, technicians who maintain and repair NGVs require specialized training. Why?
1. Natural gas is a gaseous fuel—not a liquid—and it behaves differently than liquid fuels.
2. All natural gas vehicles have unique fuel systems from their gasoline or diesel counterparts. CNG vehicle fuel systems operate at high pressures (3,600 psi), while LNG vehicle fuel systems use cryogenic fuels (-260oF).