Bi-Fuel, Dual-Fuel, Dedicated?

The CNG business often uses some pretty confusing terms to describe the different types of vehicles. Here is a quick explanation of each:

Dedicated – A dedicated CNG vehicle is one that runs only on CNG. It can be either a new vehicle with a CNG engine or a repower. In either case, the old fuel tank is normally removed and replaced with CNG Cylinders. This is a great choice for vehicles running predictable routes with access to company-owned fueling stations (for example, Food & Beverage delivery trucks and School Buses).

Mixed Fuel – The EPA calls any vehicle that blends CNG with diesel or other fuels a “mixed” fuel vehicle. In practice, there are some engines – like the Cummins/Westport ISX – that use a small amount of diesel but basically act as dedicated CNG Engines. That is to say, if you run out of CNG you are not going very far. We call these types of vehicles “mixed fuel” and, like dedicated systems, they are a great choice if you have predictable routes and you need the high torque of a heavy duty diesel engine.The main advantage of this system is that it can run 90% or more CNG while retaining many of the operating benefits of diesel. As of now, these are only available in new trucks.

Dual Fuel – Technically, a dual fuel is categorized by the EPA as a “mixed fuel” because it blends natural gas with diesel by injecting it into the turbocharger BUT there is a big difference. On a dual fuel like the American Power Group™ products we discuss here, the vehicle can still run on 100% diesel. That means if you run out of CNG you keep right on going, just like you did in the old days, running on diesel. You keep your existing diesel tanks and install additional CNG cylinders that extend the range. Depending on your load, a dual fuel system will use up to 50% CNG on average. This is a great choice for existing fleet customers that need range and fuel flexibility and do not want to go through the expense of replacing vehicles that have hundreds of thousands of miles remaining in their life.

Bi-Fuel – Bi-fuel systems are also called “switchable” systems because you can switch between gasoline or CNG. Most conversions we do for light duty (new or used trucks) are bi-fuel because they give the customer the best of both worlds. You can run on CNG as long as you have fuel in the tank and switch over to gasoline if you run out. Most modern bi-fuel systems are fully automated, switching to gasoline when they need to and then automatically switching back once the CNG tank is filled. Bi-fuel vehicles come equipped with two fuel gauges and a switch to move from CNG to gasoline if the driver desires.

Nat G® are experts in the CNG vehicle business and we can help you
decide what is best for your fleet. Call today for a free fleet assessment.