Most of the NGVs on the road today are vehicle hybrid conversions - gasoline-powered vehicles that have been adapted to run on natural gas. Virtually all of these hybrid conversions are bi-fuel, which allows operators to drive on natural gas as the primary fuel and retain gasoline as a reserve fuel, simply by flicking a switch on the dashboard.
Ontario has a well developed set of codes and regulations for conversions and service. This helps ensure all installations and systems meet the highest standards. Each natural gas conversion is customized to ensure optimal vehicle performance. Converting your vehicle is as easy as phoning or visiting your local conversion centre.
In the Greater Toronto, Niagara and Eastern Ontario areas, conversions and service are performed by Enbridge Gas Distribution authorized conversion centres.
Existing gasoline-powered vehicles have Compressed Natural Gas (CNG) components added at a conversion centre, and natural gas then becomes the primary fuel used and gasoline becomes the back-up fuel.
Storage cylinders are placed underneath vehicles like vans or pickup trucks, or in the trunk of vehicles like cabs and other cars. Stainless steel lines carry the fuel to a regulator (which reduces the pressure) in the engine compartment, then through a fuel-air mixer, and into the intake manifold to be introduced for combustion. There is a fuel selection switch (usually dash mounted) that allows the driver to manually select CNG or gasoline. A recent development has some conversion systems using fuel injection to supply the fuel directly into the combustion chamber.
This bi-fuel system allows the driver to have adequate fuel reserves in between natural gas fill-ups and actually extends the driving range over a comparable, gasoline-only vehicle. Fuel selection can be done while driving, idling or parked, and some vehicles have an automatic fuel switchover when the natural gas reaches a preset, low, pressure setting.
This is how a NGV works:
Compressed Natural Gas (CNG) enters the vehicle through the natural gas valve or receptacle (1) into high pressure cylinders (2).
When natural gas is required by the engine, it leaves the cylinders and passes through the master manual shut-off valve (3).
The gas enters the engine through the high pressure fuel line (4).
Gas enters the regulator (5), which reduces pressure from up to 3,000 psi (pounds per square inch) to approximate atmospheric pressure.
The natural gas solenoid valve (6) allows natural gas to pass from the regulator into the gas mixer or fuel injectors (7). The solenoid valve also shuts off the natural gas when the engine is not running.
Natural gas mixed with air flows down through the carburetor or fuel injection system and enters the engine's combustion chambers.
