Ram’s eTorque mild-hybrid option combines 5.7L V-8 with lithium-ion battery.
Ram’s eTorque mild-hybrid option combines 5.7L V-8 with lithium-ion battery.

Clever Technologies Help Improve Truck MPG

Wards 10 Best Engines judges are focusing closely on Ram’s eTorque 48V mild-hybrid system, Ford’s light-duty 6-cyl. diesel, Ford’s 2.7L EcoBoost V-6 (return winner) and GM’s 2.7L turbo-4 and a groundbreaking 17-mode cylinder-deactivation system available in 5.3L and 6.2L V-8s.

Detroit’s automakers understand the importance of pickup trucks for American consumers, and 2018 is bound to be remembered as a year of fierce competition in which Ford, General Motors and FCA’s Ram division launched new technologies designed to make these fullsize brutes significantly more fuel-efficient.

From Ford’s light-duty 6-cyl. diesel and Ram’s 48V mild-hybrid stop/start system to GM’s turbocharged 4-cyl. Chevrolet Silverado/GMC Sierra and 17-mode cylinder-deactivation system for the 5.3L and 6.2L V-8s, Detroit’s pickup wars have taken on a new dimension this year.

The Wards 10 Best Engines competition – celebrating 25 years of powertrain excellence – is now under way, and a number of these trucks have been evaluated in recent weeks by Wards editors, with another three weeks of testing ahead.

This year’s field of gasoline, diesel, hydrogen and electrified powertrains is expected to total 35 nominees. Winners will be announced in mid-December.

Here’s a look at engine technologies designed to make America’s most popular pickups more efficient:

The redesigned ’19 Ram 1500 relies on the trusted 5.7L Hemi V-8 and 3.6L Pentastar V-6, each mated with an 8-speed automatic transmission.

But in both applications, a new eTorque 48V mild-hybrid option boosts EPA-rated (and real-world) combined fuel efficiency by a meaningful 2 mpg (0.8 km/L).

The eTorque stop/start system replaces the engine’s alternator with a belt-driven motor/generator that adds torque on launch, smooths transmission shifts and recovers energy to a suitcase-size lithium-ion battery on the cabin wall behind the rear seat through regenerative braking during coasting and deceleration.

Standard on the base 3.6L V-6, eTorque delivers 20/25 mpg city/highway (11.8-9.4 L/100 km) with rear-wheel drive. As a $1,450 option on the 5.7L V-8, it rates 17/23 mpg city/highway (13.8-10.2 L/100 km) on RWD models. With each engine, 4-wheel drive comes with a 1-mpg penalty.

With or without eTorque – the electric motor can briefly add up to 130 lb.-ft. (176 Nm) of thrust for launch but does not change the maximum torque rating – the Hemi V-8 generates 395 hp and 410 lb.-ft. (556 Nm) with Fuel Saver Technology that deactivates four of the engine’s eight cylinders during light-load operation.

The base eTorque V-6 spins out 305 horses and 269 lb.-ft. (365 Nm) of torque. With both engines, we find the standard stop/start function totally transparent, extremely smooth and capable of shutting off the engine for up to 10 minutes at a standstill, so long as the foot remains on the brake and the transmission in Drive.

Expect eTorque to spread before long to the Jeep Grand Cherokee and other FCA vehicles.

Meanwhile, General Motors’ new-for-’19 Dynamic Fuel Management – which deactivates up to six of a V-8’s cylinders in 17 distinct “patterns” depending on driving conditions, load and demand – boosts the efficiency of the Silverado/Sierra’s 355-hp, 383 lb.-ft. (519 Nm) 5.3L V-8 to 17/23 mpg city/highway (13.8-10.2 L/100 km) with RWD, 1 mpg less with 4x4.

General Motors

DFM (pictured above)  is optional with the 5.3L but standard in the Silverado/Sierra’s 420-hp, 460-lb.-ft. (623-Nm) 6.2L V-8. GM’s long-running (since 2005) Active Fuel Management – which shuts down half of the cylinders during light-load operation – remains standard on the base 4.3L V-6 and the E-85-capable 5.3L V-8.

DFM is intelligent enough to know precisely, based on driver input, which cylinders need power and when, and for how long the fullsize pickup can run on only two cylinders.

The system is constantly adjusting the firing sequence, and it all happens smoothly, without any hint to the driver that such complexity is at play.

Another fuel-economy play for GM’s new fullsize pickups is a just-introduced 2.7L turbocharged 4-cyl. that delivers 310 hp and 348 lb.-ft. (472 Nm) and 20/23 mpg city/highway (11.8-10.2 L/100 km) with RWD, 1 mpg less with 4x4.

Relative to the Silverado/Sierra’s base 4.3L V-6, the new 2.7L produces 14% more torque, 9% more horsepower and 13% better fuel economy, while being 80 lbs. (36 kg) lighter. In addition, GM says the 2.7L propels the new trucks to 60 mph (97 km/h) in 6.8 seconds – a click faster than the 4.3L.

We have not yet driven the turbo-4, but the 2.7L – despite being small by truck engine standards – also benefits from auto stop/start and AFM, allowing it to run on two cylinders in ideal conditions. The advanced new TriPower valvetrain enables two additional valve-actuation modes: high lift (for full power) and low lift (for cruising).

The 2.7L is considered a sibling to GM’s new 237-hp 2.0L turbo-4 that debuts in the ’19 Cadillac XT4 CUV and CT6 sedan. Both engines employ Active Thermal Management, which uses an electric water pump and integrated exhaust manifold for faster warm-up, improved combustion efficiency and exhaust cooling for longer durability of the turbocharger.

Ford successfully continues its strategy of aluminum-bodied pickups powered by a range of 2.7L, 3.3L and 3.5L turbocharged EcoBoost V-6s, naturally aspirated 3.3L V-6s and 5.0L V-8s, and a new-for-2018 3.0L Power Stroke turbodiesel V-6.

Ford’s most fuel-efficient gasoline 2.7L truck V-6 (a 2018 Wards 10 Best Engines winner) offers 325 hp and 400 lb.-ft. (542 Nm) with 20/26 mpg city/highway (11.8-9.0 L/100 km) with RWD and 19/24 mpg (12.4-9.8 L/100 km) with 4x4.

The F-150’s available 250-hp, 440-lb.-ft. (597-Nm) turbodiesel is rated by the EPA at 22/30 mpg (10.7-7.8 L/100 km) with RWD and 21/28 mpg (11.2-8.4 L/100 km) with 4x4.

This is the first fullsize truck to achieve a 30-mpg (7.8 L/100 km) highway rating, but we’ll bet GM’s soon-to-come Silverado Duramax I-6 turbodiesel will reach that mark as well.

Ram offered its 3.0L turbodiesel V-6 last year in previous-generation fullsize pickups, which stay in the market as Ram 1500 Classic. In 2019, FCA says both the Classic and all-new Ram 1500 will be offered with a light-duty diesel.

No special new technologies yet from Toyota, whose Tundra offers a choice of 310-hp 4.6L or 381-hp 5.7L V-8s rated at 15/19 mpg (15.7-12.4 L/100 km) and 13/18 EPA mpg (18.1-13.0 L/100 km), respectively, with RWD.

Same is true for Nissan, whose Titan pickups are powered by a 390-hp 5.7L gas V-8 rated at 15/21 mpg (15.7-11.2 L/100 km), while its heavier-duty Titan XD adds an (unrated) available 310-hp 5.0L turbodiesel V-8.

– with Tom Murphy

TAGS: Engines
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