Was I brainwashed by a pair of Roush executives during a recent visit to their headquarters in Livonia, Mich.? Or, in spite of the hoopla over natural gas, is propane the one alternative fuel that really does make the most sense right now? The answers: Of course not—I’m a skeptical reporter! And yes, it probably is, at least for light trucks.
This pep session on propane occurred before I was turned loose with a 2009 Ford F-250 SuperDuty pickup equipped with a Roush fuel system. Todd Mouw, vice president of sales and marketing, and Brian Carney, director of marketing, told me about propane’s low price and wide availability. It typically costs $1.50 to $2 per gallon less than gasoline or diesel, and is sold at 3,000 locations in the United States.
That’s many more than natural gas, which many Americans believe is the fuel of the future. Those folks aren’t wrong, as experts say we have more than 100 years’ supply of natural gas. And as everyone and his brother knows, we’re seeing a drilling boom in several states. But more than half of all propane here is made from natural gas, so bring it on. Propane is also called liquefied petroleum gas because it historically was produced as a byproduct of oil refining.
Users of propane-fueled vehicles don’t tank up at places that fill barbeque bottles, but at outlets that sell “autogas,” which is what propane’s called elsewhere in the world. Millions of cars and trucks overseas burn it, say boosters of the product. Only about 270,000 vehicles in the U.S. are equipped to burn autogas, and it’s Mouw and Carney’s mission to boost that number. That’s why the Roush F-250 and other demonstration vehicles exist.
Autogas
Autogas is sold with road taxes attached and is best obtained in bulk. Roush has a 1,000-gallon tank outside its shop a mile or so west of its headquarters, and it paid $1.99 a gallon for a recent replenishing. The tank and its pump might cost $10,000 for a fleet to obtain, Mouw said. That’s a small fraction of a fleet-size natural gas facility; prices depend on storage and pumping capacity, but I’ve seen figures of $900,000 for CNG to $4.5 million and more for LNG facilities.
The cost of converting a light truck such as the F-250 to compressed natural gas is about $25,000, Mouw said, but the propane system on this truck would be priced at $11,000 to $12,000. That’s mostly because the steel propane tank is pressurized to a modest 250 to 300 psi when full. Natural gas is stored at 3,600 or more psi, so its tank must be much stronger and tested to ensure safety. Thus a set of CNG bottles is much more costly, and so is a cryogenic tank for LNG. Government incentives are available in some places to offset conversion costs, but propane can make a decent business case on its own, he and Carney said.
In the Roush conversion, the stock gasoline system was discarded and the propane fuel system installed. It consists of the special 55-gallon steel tank in the bed, behind the cab; fuel lines, fuel rack, pump and controls; and injectors on the engine’s heads. The tank is obvious, but everything else is beneath the truck’s skin. Unlike old dual-fuel systems—and recently announced products for Ford, General Motors and Ram pickups, which burn both gasoline and natural gas—the Roush system uses only propane.
The engine’s electronic controls were modified to consume propane, which has an octane rating of 105 instead of regular gasoline’s 87, he explained. Propane contains 10 to 15 percent less energy as measured in British thermal units; so if a truck’s getting 15 mpg on gasoline it’ll get about 12.5 mpg on propane. But propane’s cheaper, so the total fuel cost is still considerably less.
At the Roush filling station, Carney showed me how the Ford’s tank is topped off. It’s a lot like gasoline, except you screw a sleeve on the stout nozzle onto the truck’s special filler neck. Then you trigger it, and the tank fills in a few minutes. There’s a faint pop as you pull off the nozzle and you might get a whiff of the gas. Propane is safer than gasoline if there’s a leak because it quickly evaporates and dissipates, he said.
Now we’re set to go, except that the Roush truck’s starting sequence is a bit different. Insert the key into the column-mounted ignition switch and twist it like you’re cranking over the engine. Then release it, and after two or three seconds, the engine starts. During that pause, propane vapors are purged from the fuel lines and replaced with liquid fuel. Pop the transmission lever into D and drive away.
The truck’s behavior is “remarkably unremarkable,” Mouw remarked, and he was right. The truck’s 300-horsepower Ford 5.4-liter V-8 was smooth and gutsy, and ran like it was using gasoline. Its 5-speed automatic transmission shifted just like it’s supposed to, because it had no idea what the engine was burning. Propane burns cleaner than gasoline so emits fewer pollutants, and there are stories of engines running twice as long as usual because its cylinders stay clean. Roush makes no claims about engine life, but does note that some users extend drain intervals because crankcase oil stays clean, too.
My drive over Livonia’s sometimes rough concrete streets had me contending with the empty F-250’s stiff ride, which I expected from a 3/4-ton’s suspension. Besides, it was a tighter-riding 4x4, which had a standard, manually operated transfer case; I didn’t engage it, but noticed that it had a hump-mounted lever that was far forward, extending inconveniently under the dash. This truck had the basic XL trim with a vinyl floor that shrugs off mud and such. Its cloth-covered seats were comfortably contoured, and all gauges and controls were easy to use. It was a work truck, but a pretty nice one.
Right now Roush produces propane conversion kits for only Ford trucks. This is an offshoot of its work on Ford Mustangs, which it upgrades for high-performance street and race use, Carney said. Years before, the company’s founder, Jack Roush, worked as a Ford engineer. It currently does custom engineering for other auto makers, so it might have propane products for them some day. Installation of the systems is done by Roush technicians at its own facilities and by authorized upfitters such as Knapheide and Adrian Steel.
Propane’s downsides
Aside from the conversion cost, it’s different, and a user has to have a fuel source. These can be found online, but on the supply score it’s currently better for vehicles that stay local. Price varies with locales, and might be more volatile than for natural gas. As for safety, a few days after visiting Roush I attended a Cummins event where an engineer disagreed with my casual description of a propane vehicle’s tank as “a big barbeque bottle.”
“No!” he barked. “They’re more than that.” They have to be—and Roush ensures that they are—because in everyday use, propane expands when exposed to high heat. In extreme cases, tanks can and have exploded. Until recent years Cummins made and sold propane-fuel engines, but the market dwindled and the builder has instead embraced natural gas with certain products, such as the ISL-G medium/heavy-duty engine. The propane experience taught Cummins people that, with safeguards, it’s a decent fuel for cars and light trucks but not for heavier trucks.
So I’m not brainwashed anymore. But the dollar figures tell me that propane autogas still seems a good idea where the fuel and engines that efficiently burn it are available. Look it up at www.roushcleantech.com and elsewhere, then talk to fleet managers who use it and see if they’re not right.
