CNG General Information
Natural gas is a mixture of hydrocarbon gasses with a high concentration of methane gas, which burns completely into carbon dioxide and water, resulting in lower emissions than with diesel or gasoline.
Natural gas is less energy dense than diesel, therefore, a larger volume of natural gas is required to produce the same power. This is one reason for the slightly lower maximum power in natural-gas-powered vehicles. The power difference is a reduction in maximum power only and does not affect normal driving. The power reduction is evidenced only in wide-open throttle, high-torque conditions.
Important: The natural gas fuel system should be routinely inspected for gas leakage. Use a natural gas detector to check the fuel tanks, fuel filtering and regulating mechanisms, and the fuel lines. If necessary, replace leaking fuel tanks; repair or replace any lines, devices, or connections that are leaking.
Natural gas is nontoxic, but it can cause asphyxiation in certain circumstances. Commercial compressed natural gas normally contains an odor-producing chemical, which enables users to detect gas leaks, but a natural gas detector is recommended for checking for leaks.
A typical natural gas fuel system consists of:
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Fuel supply containers or tanks storing the gas at high pressure.
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A pressure relief valve and manual shutoff valves.
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A filling connection with a check valve to prevent the gas from flowing back out of the connection.
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A valve that automatically closes if the engine stops.
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A high-pressure fuel filter and a low-pressure fuel filter.
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A pressure regulator to reduce the fuel tank pressure to the lower pressure needed for the engine.
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A gas-air mixer to produce a flammable mixture for the engine.
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A pressure gauge to indicate the fuel supply in the tanks.