Diesel made a comeback in the U.S. at the beginning of the 2010s, boosting prospects for the compression-ignition engine in this part of the world. But alas, the VW emissions scandal ruined everything in 2015.
Six years after Volkswagen hit the final nail in the coffin of diesel-powered cars in the United States, compression-ignition technology soldiers on in a select few vehicles. Most of them are body-on-frame designs, predominantly trucks and SUVs. The only exceptions come from Land Rover in the guise of the Range Rover and Range Rover Sport, which use the TDV6, also known as Power Stroke in the 2021 model year Ford F-150 half-ton workhorse.
After covering the Duramax family of powerplants for the U.S. market, it’s high time for us to remember what kind of diesel options Fiat Chrysler Automobiles currently offers. The smallest automaker of the Big Three in Detroit boasts just two under the EcoDiesel and Cummins monikers.
The L630 for the U.S. market dates back to 2011 when Italian diesel-making company VM Motori debuted the A630 with 3.0 liters of displacement and a 60-degree V angle. Constructed from graphite iron for the block and lightweight aluminum for the heads, the 10-year-old engine design was found to have emissions defeat devices on MY 2014 through 2016 vehicles.
Previously offered in the WK2-generation Jeep Grand Cherokee, the L630 is currently found under the hoods of the Ram 1500 light-duty pickup, Jeep Wrangler off-road utility vehicle, and Jeep Gladiator off-road pickup. The 1-2-3-4-5-6 firing order and the 60-degree V angle optimize the firing loads and inertia management, therefore eliminating the need for a balance shaft.
Heat-treated individual bearing caps for the aluminum heads reduce friction and NVH levels. The forged steel used for the connecting rods and crankshaft helps with this engine’s durability, along with aluminum-alloy pistons that benefit from oil jets. The variable-geometry turbocharger, automatic tensioning single-belt drive, MultiJet common-rail injection, cooled exhaust gas recirculation, selective catalytic reduction, diesel exhaust fluid system, as well as high-temperature glow plugs also need to be mentioned.
In the Ram 1500 and Jeep Wrangler/Gladiator twins, the EcoDiesel develops 260 horsepower and 480 pound-feet or 442 pound-feet (650 or 600 Nm) of torque. Available in conjunction with an eight-speed automatic transmission, this fellow tops 26 miles per gallon (9 liters per kilometers) on the combined driving cycle according to the Environmental Protection Agency.
Photo: Ram
The other diesel engine that Fiat Chrysler sells today is the 6.7-liter Cummins in the Ram heavy-duty truck lineup, a torquey behemoth saddled with an extensive range of emissions control systems. A very different animal from the 5.9 from the good ol’ days, the 6.7 is offered in two flavors.
For the standard-output version, customers are treated to 370 horsepower and 850 pound-feet (1,152 Nm) of torque. The high-output version of the straight-six Cummins turbo diesel tops the heavy-duty truck segment with 400 horsepower and a decidedly outrageous 1,075 pound-feet (1,458 Nm).
When properly equipped, the 2500 and 3500 with this engine can tow up to 20,000 and 37,100 pounds (9,071 and 16,828 kilograms). If payload is highest on your list of priorities, the Ram 5500 Chassis Cab is your workhorse.
Last updated for the 2021 model year Ram heavy-duty lineup, the 6.7-liter Cummins flaunts new calibration, a.k.a. more boost, for the sliding nozzle variable-geometry turbocharger. The fuel delivery system, which is capable of sustaining 2,000 bars (29,008 psi), was treated to an increased flow rate.
One advantage of the straight-six layout over the Duramax V8 and Power Stroke V8 is smoothness. Ram also sweetens the deal with more sound-insulating materials than before, an acoustic windshield, as well as active noise cancellation for top-of-the-line trim levels of the Ram 2500 and 3500.
The Cummins-Ram partnership dates back to the 1989 model year when the B-series engine in the Dodge Ram was coupled to the heavy-duty version of the TorqueFlite A727 automatic or a five-speed manual transmission. The 2021 Ram HD with the 6.7-liter mill features two automatics: the 68RFE for the standard-output version and the Aisin AS69RC for the H.O. version.
After a 1:43 scale model of a Ferrari 250 GTO sparked Mircea's interest for cars when he was a kid, an early internship at Top Gear sealed his career path. He's most interested in muscle cars and American trucks, but he takes a passing interest in quirky kei cars as well. Full profile
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