CNG Systems

Question 1

What does CNG stand for?

Accepted Answer

Compressed Natural Gas

Answer

CNG is an acronym that stands for Compressed Natural Gas. It is a fossil fuel substitute for gasoline (petrol), diesel, or propane fuel, used in internal combustion engines. Natural gas is compressed to less than 1% of its volume at standard atmospheric pressure.

Question 2

Which gas does CNG contain?

Accepted Answer

Methane

Answer

Compressed Natural Gas (CNG) is primarily composed of methane (CH4). Methane is the simplest hydrocarbon and the main component of natural gas, making it the primary fuel source when natural gas is used in its compressed form.

Question 3

What does the shut-off valve at the compressed natural gas cylinder serve as?

Accepted Answer

To cut the gas flow from tank to lines.

Answer

The shut-off valve at the compressed natural gas cylinder is a critical safety component. Its primary function is to manually or automatically cut off the flow of gas from the high-pressure storage tank to the vehicle's fuel lines, preventing gas leakage or uncontrolled release in case of an emergency or during maintenance.

Question 4

What is the required rated service pressure for fuel supply cylinders?

Accepted Answer

At least 2400 psig at 70°F

Answer

Fuel supply cylinders for Compressed Natural Gas (CNG) must be designed to withstand high pressures safely. The required rated service pressure is at least 2400 psig (pounds per square inch gauge) at a temperature of 70°F (21°C) to ensure structural integrity and prevent rupture under normal operating conditions.

Question 5

What must be used when venting CNG into the atmosphere?

Accepted Answer

A vent pipe or stack

Answer

When venting Compressed Natural Gas (CNG) into the atmosphere, a vent pipe or stack must be used. This safety measure ensures that the gas is discharged upwards and away from ignition sources, personnel, and enclosed spaces, allowing for safe dispersion and preventing the accumulation of flammable gas at ground level.

(CNG) Compressed Natural Gas Practice Test

(CNG) Compressed Natural Gas Practice Test

CNG Systems