Diesel Comes to Ram 1500
Half-ton pickups are undergoing significant changes under the hood,
as OEMs address fuel efficiency requirements without giving
way in the capability arena. But no change of late is bigger
than what Ram is doing: putting a diesel in the Ram 1500.
#HP #Fiat #Dodge
Bob Hegbloom, director, Ram Truck Brand, says that for years, light-truck buyers have been asking for diesel engines. Hegbloom says that these people understand diesels, understand that they provide excellent fuel efficiency and the kind of torque that is necessary for doing things like towing. But Hegbloom says that there has been a significant problem, one that has kept those engines out of light trucks like the Ram 1500: the price of gasoline to diesel fuel was such that it didn’t make a heck of a lot of sense from an ROI perspective for the customers. So in the mean time, developments have been made in diesel technology, so diesels have become more efficient, smoother, quieter, and cleaner than their pre-decessors. What’s more, because it is offered with an eight-speed automatic transmission (the only eight-speed in the segment), the diesel can operate at a more efficient range than would be the case with a six-speed. In fact, Hegbloom says that with a six-speed, there wouldn’t be much in the way of performance advantage for a diesel in the 1500. But now there is.
So the 2014 Ram 1500 is the first light-duty full-size pickup to offer a diesel in the U.S. market in this century.
It is a 3.0-liter, 24-valve, dual-overhead-cam turbocharged 60° V6. It provides 240 hp @ 3,600 rpm and 420 lb-ft of torque @ 2,000 rpm. It is called the “EcoDiesel.”
When we talked with Hegbloom, the EPA fuel efficiency numbers weren’t set. But he explains that it will be better than 25 mpg highway, which is what the 3.6-liter, 60° V6 Pentastar provides—and he notes that that 25 mpg number is best-in-class. But the key thing with the diesel is that it provides the sort of performance characteristic of the 5.7-liter, 16-valve 90°, HEMI V8. That engine provides 395 hp @ 5,600 rpm and 410 lb-ft of torque @ 3,950 rpm. Note that the diesel provides a whole lot more torque. And it is also worth noting that the EPA fuel economy for the 1500 with the HEMI and a ZF 8HP70 automatic transmission—the same eight-speed transmission that is standard with the EcoDiesel—is 15/22 mpg, city/highway. And when it comes to towing, the in 2WD, two-door, long bed configuration, the EcoDiesel will tow up to 9,200 lb. A comparable truck with the V8 is 10,450 lb.
The 3.0-liter diesel is also being deployed by the Jeep Grand Cherokee, where its estimated fuel efficiency is 30 mpg highway. Hegbloom says that the Ram’s number will be less than that, given the differences in mass and aero profiles of the two vehicles.
As mentioned, the 3.6-liter V6 is the base engine. To go from that to the 5.7-liter V8 there is a price increase of $1,650. To go from the base to the 3.0-liter diesel, the price increase is $4,500. Yet Hegbloom says that the ROI for someone who drives ~15,000 miles per year would be within that year.
The source of the diesel engine is VM Motori of Cento, Italy. Not surprisingly, 50% of VM Motori is owned by Fiat Powertrain. Surprisingly, the other half was owned by . . . General Motors.
Mike Cairns, chief engineer, Ram Truck, breaks down the characteristics of the turbo-diesel:
• The engine has a bedplate and cylinder block of compacted graphite iron, which provides strength, durability, and provides good NVH characteristics. The cylinder heads are heat-treated aluminum. (Given that the compression ratio is 16.5:1, we wonder whether aluminum heads are up to the task of dealing with the compression combustion, so we ask Jamie Standring, who heads up Ram Powertrain Engineering, who says that it can readily handle it and that it has been now been used in several diesel applications for years.) The structural oil pan is aluminum, as well.
• The crankshaft and connecting rods are forged steel. Pistons: aluminum alloy.
• The EcoDiesel uses Fiat’s MultiJet II common rail fuel-injection system. It provides 2,000 bar (29,000 psi) of line pressure. What’s notable about the MultiJet II system is that it allows fuel-injection events to occur up to eight times per cylinder cycle. What’s known as “injection rate shaping”—modulating the interval between two consecutive injections—helps minimize noise from the injection event.
• To help address emissions (it meets 50-state emissions compliance for both tier II and bin 5) there is an exhaust gas recirculation (EGR) system that deploys electric valves rather than the more-conventional pneumatic type. The selective catalytic reduction (SCR) system uses a diesel exhaust fluid system; the urea-based fluid is held in an eight-gallon tank, a quantity sufficient to handle, on average, 10,000 miles of driving.
• Hegbloom acknowledges that light-duty truck buyers typically have a deep commitment to brand. But because of the EcoDiesel, he says, “This might allow us to bring in a Ford or Chevy loyalist who never considered us in the past.”
It is the classic competitive advantage.
While the whole notion of minivans might provoke an involuntary eye roll among some people, here’s an interesting fact: so far this year, through the end of March, Chrysler delivered 31,616 Town & Country minivans, which makes it, by far, the biggest selling vehicle in the brand’s showroom.
It is a pretty good rule of thumb that automotive journalists tend to like cars that go fast.
Dan Nicholson is vice president of General Motors Global Propulsion Systems, the organization that had been “GM Powertrain” for 24 years.