2012-13 Ram 2500 CNG Hemi: BiFuel Pickup Trucks
The Ram 2500 Heavy Duty CNG pickup, sold only to fleet and commercial customers, can run on either compressed natural gas (CNG) or gasoline. It starts up using gasoline, switches immediately to CNG, and, if CNG is exhausted, switches back again to gasoline — all without any need for driver input. Natural gas is usually domestically sourced in the United States and Canada, reducing dependence on imported oil. [See CNG Dodge vans of the 1990s]
Allpar predicted the Hemi-based CNG system in September 2011. Information of the time indicated that the CNG version adds 780 pounds to the weight of the vehicle, mainly due to the twin 130-liter tanks under the pickup bed, covered by high-strength steel (the truck also comes with an 8-gallon gas tank; Canadians can opt for a 35-gallon gas tank). Ram chief Fred Diaz denied, then, that Ram was making a CNG capable engine, a half-truth: they were not making production versions but they were making prototypes.
The payload is 1,580 lb, with 7,650 lb of towing capacity, front GAWR of up to 5,200 lb, and a four-foot-eight-inch usable bed length. The Ram 2500 has integrated 4- and 7-pin connectors along with a Class IV hitch receiver and trailer brake controller (with customer-programmable electric or electric-over-hydraulic trailer brake options).
The Ram 2500 CNG system includes redesigned heads and valve seats, an additional CNG-specific fuel rail, new spark plugs, and a new computer. Ram engineer Doug Killian said the Ram CNG is made “entirely in-house. That makes us unique in that we offer a pickup that comes out of our [Saltillo] assembly plant, starts life right on the assembly line with the diesels and the Hemis, and we build up the CNG system right there. We actually run it on the CNG, do all of our development and the final testing in the plant, ship it out with CNG in the tanks.”
The range on CNG is estimated at 255 miles, and the backup gasoline supply extends the range to 367 miles. The CNG tanks hold the equivalent of 18.2 gallons of gasoline (14.5 liters of CNG at 3,600 psi are equivalent to one gallon of gas). At launch, CNG cost $1.25 per “gallon-equivalent” less than gasoline. Ram’s Doug Killian said, during our test drive,
The truck will run on only CNG. If you look down between the gauges, you see the letters CNG? That’ll read the word “gas” if it’s running on gasoline. This truck is designed to run exclusively on natural gas, but it has gasoline on board for two reasons. One is the natural gas infrastructure isn’t too broad right now, so sometimes finding natural gas can be a challenge. If you run out of range – they call it “range anxiety” in the CNG world now– you can always fill up with gasoline to get you to another CNG filling system.
The gasoline on board also helps with cold weather operation. Natural gas is more difficult to burn in cold weather so we need to let the engine warm up such that there are no issues with stumbling or hesitation or stalling or anything. That’s the only time the gasoline is ever used [if you have CNG in the tank].
Chrysler had built and sold CNG V8 trucks before — B-vans were sold in the late 1990s and 2000s which ran on natural gas. We asked who had engineered the new ones — Chrysler or Fiat. Doug Killian said:
For the engines, we used both. The B-van was done with our Canadian development center. They had done a lot of the engineering development work for both the power train and the fuel system. Now we have the leverage of Fiat and their experience, that we could rely on them along with our partners in Canada — it’s a Chrysler Canada engineering operation. So we used both. ...
The B-van was developed primarily in Chrysler Canada. This truck, the Ram CNG, was developed in our engineering operations in Auburn Hills at the Chrysler Tech Center. The development testing was done at our proving grounds here in Chelsea in Arizona, and all the crash testing and powertrain development was all done by Chrysler Engineering. This is unique to us, our competitors send an unfinished vehicle out, another company then puts their system on a Chevy or Ford and delivers it. In this case it’s a one-stop shopping for our customers. They have the backing of Chrysler Engineering who developed the rest of the Ram family.
[It] starts life right on the assembly line with the diesels and the Hemis, and we build up the CNG system right there. We actually run it on the CNG, do all of our development and the final testing in the plant, ship it out with CNG in the tanks.
We took the truck over the “bad road” segments of the oval course at the Chelsea Proving Grounds. Acceleration was unimpressive but sufficient; running on CNG, the Ram Hemi is not quite as strong as it is on gasoline, though it’s sufficient for regular driving and towing a reasonable load. Doug Killian added:
We considered the horsepower rating and the ability for this to be a work truck. We worked with the companies that operate fleets and listened to them; if they’re going to run a vehicle on natural gas, what would they want it to be? They told us clearly the 2500 is the truck that they would use. ... loading a trailer behind us and loading gear and a cruise into it…
Our development trucks get tested for durability and just get punished every day. Some of our durability roads at the proving grounds here are awful. You get a little flavor of it there, but it’s orders of magnitude worse. This road, we use for developing our riding handling, springs and shocks and tires.
We realize that the bed is going to see some pretty severe use. We developed a robust tank cover system and we used the Type-1 CNG tank, which is all steel and the most robust of natural gas storage tanks. Since these can store at 3,600 PSI, we need to have robust parts there because you get a load of gravel in the back or run this thing up on a two-track or off-road, going to a natural gas well or servicing phone lines or whatever they’re going to do with these, we don’t want owners to have to worry.
CNG trucks: availability and benefits
CNG vehicles emit 20% less CO2 than gasoline vehicles and generate fewer greenhouse gasses in fuel production. Dedicated NGVs produce, on average, 70% less carbon monoxide, 87% less non-methane organic gas, and 87% less NOx than traditional gasoline powered vehicles.
There are around 1,500 CNG fueling locations across the U.S., half of which are accessible to the public; large fleet operations frequently install both quick-fill and slow-fill CNG fueling stations. The Ram CNG’s bi-fuel capability allows it to operate on gasoline indefinitely, until CNG can be added.
A 5-year/100,000-mile powertrain limited warranty covers the HEMI V-8 and transmission, and adds internal engine components specific to CNG. The truck also has the standard 3-year/36,000-mile bumper-to-bumper limited warranty. Specific to the CNG engineering, this covers all non-engine components, including the tanks, storage compartment and fuel filler equipment.