Alternative fuels seem to be all the rage these days, but one of the few that actually seems to make sense to us is compressed natural gas, also known as CNG. CNG is natural gas that has been compressed to less than one percent of its volume at standard atmospheric pressures. It is clear, odorless, non-corrosive, and clean-burning fuel that is drawn from natural gas wells or crude oil production and is a plentiful resource in North America, with an estimated 120-year supply available.
In addition to the abundant domestic supply, CNG is about half the cost of gasoline and releases substantially fewer emissions when burned. Because it has a narrow range of flammability and due to it being lighter-than-air, CNG is considered to be as safe as, or safer than gasoline, as it dissipates rapidly into the atmosphere when released.
To prove the concept for a fleet-based off-road vehicle, the team at Venchurs took a ’12 Super Duty equipped with a 6.2L V-8 and converted it to run on either gasoline or CNG. Their bi-fuel technology allows virtually seamless on-the-fly transition from one fuel to the other (although we did notice a momentary hesitation during one of our switchovers) and if one fuel runs out, the vehicle will automatically switch over to the alternate fuel on board. With all of the tanks topped off, the Venchurs Super Duty has an impressive range of over 600-miles.
A dash-mounted gauge monitors the CNG fuel level.
The Venchurs Super Duty concept was decked out in a park ranger livery and in addition to the bi-fuel conversion was upgraded with a 2-inch Superlift leveling kit, Superlift Superide SS/Bilstein shocks, LT325/60R20 (35-inch) BF Goodrich Mud-Terrain T/A KM2 tires, Asfir skidplate, Fab Fours bumpers, a Warn 16,000-pound winch, IPF driving lamps, and AMP Research Bedsteps. Rounding out the conversion is a dash-mounted Ford Racing fuel gauge to monitor the CNG system.
Out on the highway, the Venchurs F-250 performed no differently than an otherwise-stock Super Duty. Acceleration, passing power, and general all-around drivability were exactly what you would expect. In fact, an experienced user would have a hard time detecting the switch in fuels, which is probably the point.
Under the hood, the 6.2L V-8 looks completely stock, but uses a special gaseous injection
Despite an octane rating of 130, we didn’t notice much of a performance improvement, if any, while running on CNG. This is more indicative of the engine being based on gasoline and tailored for a gasoline-friendly compression ratio (in the case of the 6.2L it is 9.8:1), while natural gas performs optimally at something closer to 13:1. Aiding in fill-ups, the CNG fill port occupies the same place under the fuel door as the urea fill does in diesel models. Overall, we found the Venchurs bi-fuel conversion to be as OE-like as possible in its performance and execution.
The high-pressure CNG cylinders are mounted in an enclosure in the bed.
Even though CNG fills up an entire column under “Pros,” it still has a fair amount of drawbacks to overcome, not the least of which is the extra space it takes to store the heavy, high-pressure cylinders. In the case of the Venchurs F-250, it means less storage capacity in the bed, as the tanks are mounted against the front of the cargo box in an enclosure. CNG is also harder to find with an estimated 1,100 filling stations in the US, with only about half of those open to the public, which is an important consideration since CNG provides less range from a GGE (gasoline gallon equivalent) than a gallon of gasoline. As a contrast, the gasoline infrastructure benefits from almost 160,000 gas stations in the U.S. that are open to the public. CNG conversions are also cost-prohibitive, ranging between $10,000 and $12,000, depending on the vehicle.
Fortunately, there are tax credits and other financial incentive programs that are available to help with the purchasing or conversion costs. Another cost-reducing option is the installation of home refilling stations, which further drop the price of the fuel and in some places reduces the taxes on the fuel.
If some of the quirks with CNG can be worked out and as the conversion costs become more affordable and are no longer a barrier of entry, CNG could quickly become the alternative fuel of choice in the future. We know finding a substitute to gasoline is a long road, but the CNG highway is one we wouldn’t mind driving on.
Hot: Maintained performance, seamless transition, clean burning, affordable
Not: Conversion cost, reduced range, limited infrastructure
Our Take: An alternative fuel worth considering
Venchurs Vehicle Systems