2013 Ford Mustang GT Bi-Fuel - front three-quarter view
Highly intrigued, we recently visited a Southern California Gas Company office to check out several hybrid vehicles promising something new. Unlike more commonplace gasoline-electric hybrids, we were there to evaluate innovative gasoline-compressed natural gas (CNG) hybrids – yes, they run on unleaded gasoline and compressed natural gas. According to the experts on hand, this arrangement delivers extended range and reduced emissions while chipping in with lower operating costs than pure-gasoline vehicles. There are advantages over its gasoline-electric counterparts, as well.

The program is part of a three-way collaboration between The Carlab, a Southern California-based automotive consulting firm, Landi Renzo USA, a company specializing in alternative fuel solutions, and America's Natural Gas Alliance, a group that promotes CNG. Long story short, the team has engineered a way to allow a modified internal combustion vehicle to seamlessly switch between two fuels (gasoline and CNG) with no driver intervention. In theory, and if it works as well as promised, it's a win-win for the vehicle owner and the environment.

Parked at the Gas Company office were six different gasoline-CNG hybrid vehicles. To demonstrate the technology's versatility (just about any gasoline vehicle may be modified) Carlab brought a varied assortment of bodystyles, each from a different automaker. After taking a quick glance at the half-dozen in the parking lot, we made a beeline for the performance-oriented Ford Mustang GT – a 2012 model – with the six-speed manual gearbox.

Driving Notes:
  • The conversion to bi-fuel requires the installation of a four-gallon composite CNG tank (3,600 psi) beneath the rear trunk liner, CNG bi-fuel port injectors, a special fuel controller, integrated dash display and some other hardware. With the exception of the blue "CNG" diamond on the rear of the trunk, the exterior of this Mustang hybrid offers little clue to what type of fuel it consumes. The interior of the cabin is equally discreet, but a closer look at the digital panel on the instrument cluster reveals an OEM-like four-bar "GGE" gauge with the tank level. Peering under the hood, the only obvious changes are the new injectors (the CNG tank is filled through a nipple located behind the OEM fuel filler door). The conversion adds about 150 pounds to the coupe's curb weight.
  • From a driver's standpoint, vehicle operation is unchanged. A sophisticated controller determines which fuel is best for the job (or a mix of both), so gasoline is often used for the cold start. However, after a few moments of operation, the vehicle will seamlessly switch to more efficient CNG operation for partial throttle and during cruising. A firm press on the accelerator immediately delivers gasoline into the combustion chamber, bringing the Mustang's full 420 horsepower on tap. During our drive of the manual transmission coupe, we noticed a very slight delay – almost a hiccup – at about 3,000 rpm during the bi-fuel transition (we later drove a BMW X3 automatic, and the changeover from CNG to gasoline was unnoticeable). Once it made it over this hurdle, power delivery was smooth and strong.
  • In addition to the improved efficiency and lack of power compromise, the CNG tank provides a bonus boost in vehicle range. The tank is good for about 55 extra miles, so it adds upwards of 20 percent to the Mustang's cruising distance. That's a nice plus.
  • Carlab is touting the gasoline-CNG bi-fuel model as an alternative to plug-in hybrids. Instead of heavy battery packs requiring nightly charging, they envision a world where owners would have a home CNG refill station that would make fueling effortless and bring prices down to about $.80/gallon - a fraction of the price of gasoline.
  • The cost of conversion to the typical passenger vehicle is slightly less than $3,000 (assuming a production rate of 20,000 annual units), meaning the average owner would earn back the cost after about 2.2 years - that's quicker that the return on investment for a Nissan Leaf, Chevrolet Volt or Toyota Prius, says Carlab.
  • While we were impressed after our first experience with the hybrid gasoline-CNG vehicles, natural gas still has a mountain of hurdles to overcome. Even if one assumes that the non-renewable resource may be easily obtained, the refueling infrastructure will take many years to build.