Bi-fuel systems are capable of operating on two fuels independently. This is unlike other terms such as dual-fuel and mixed-fuel systems.
“While the terms are sometimes interchanged and confused as similar, the fuel systems’ components are distinctly different,” points out Mike Taylor, director of autogas business development for PERC.
Dual-fuel and mixed-fuel systems can offer one of two options:
- Operate on two fuels simultaneously.
- Substitute a secondary fuel, such as propane, for a primary fuel like diesel.
“Both fuel systems are popular and provide savings for fleets,” Taylor says. “However, bi-fuel systems continue to provide the greatest long-term savings over the life of a vehicle.”
Dual-fuel, explains director of government relations for Blue Star Gas Darren Engle, uses fuels together. “Those would be diesel-propane blend systems, a CNG-diesel blend system, anything that is actually combining fuels or using two actual fuel sources at the time of combustion.”
The reason alternative fuel systems can be confused stems from the fact that when this technology was budding, the terms bi-fuel and dual-fuel meant the same thing.
“About eight years ago, with the introduction of propane and CNG, these alternative fuels were combined with diesel to enhance the performance and emissions of diesel engines,” explains Calvin Thorn, director of warranty and customer service for CleanFUEL USA. “Dual-fuel is now commonly used to describe systems where propane or CNG is added to the engine while still burning diesel fuel so the engine burns two fuels – or dual-fuel.”
The term hybrid is used when both gasoline and electricity are utilized to power a vehicle.
Dedicated, mono-fuel systems are also available for those seeking an alternative to traditional gasoline or diesel powered vehicles. Unlike a bi-fuel system, which involves adding an alternative fuel source to the original gasoline architecture, a dedicated system replaces the base gasoline system creating a vehicle powered solely by propane, CNG or another alternative fuel.
