How Do Natural Gas Cars Work?

Compressed natural gas (CNG) vehicles work much like gasoline-powered vehicles with spark-ignited internal combustion engines. The engine functions the same way as a gasoline engine: The fuel-air mixture is compressed and ignited by a spark plug. The natural gas is stored in a fuel tank, or cylinder, typically at the back of the vehicle. A CNG fuel system transfers high-pressure natural gas from the fuel tank to the engine. The pressure is then reduced to a level compatible with the engine fuel management system. Learn more about natural gas vehicles.

Key Components of a Natural Gas Car

Battery: The battery provides electricity to start the engine and power vehicle electronics/accessories.
Electronic control module (ECM): The ECM controls the engine's performance, fuel efficiency, and emissions; safeguards the engine from abuse; monitors the operation of the vehicle; and troubleshoots mechanical problems.
Exhaust system: Channels the exhaust gases from the engine out through the tailpipe.
Fuel filler: A filler or "nozzle" used to add fuel to the tank.
Fuel injection system: This system inserts fuel into the engine's combustion chambers for ignition.
Fuel line: A metal tube or flexible hose (or a combination of these) allows for transferring fuel from the tank to the engine's fuel injection system.
Fuel tank (compressed natural gas): Stores compressed natural gas on board the vehicle until it's needed by the engine.
High pressure regulator: Reduces and regulates the pressure of the fuel exiting the tank, lowering it to an acceptable level required by the engine 's fuel injection system.
Internal combustion engine (spark-ignited): In this configuration, fuel is injected into the intake manifold or combustion chamber and combined with air, and the air/fuel mix is ignited by the spark from a spark plug.
Manual shut off: Allows the vehicle operator or mechanic to manually shut off the fuel supply.
Natural gas fuel filter: Traps dirt and other particles to prevent them from clogging critical fuel system components, such as fuel injectors.
Transmission: The transmission transfers mechanical power from the engine and/or electric traction motor to drive the wheels.


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