Ford F-Series Super Duty Power Stroke Diesel is cleanest ever – fuel economy greatly improved
The all-new 2011 Ford F-Series Super Duty delivers best-in-class
torque, horsepower, towing and payload capability ““ and does it all more
efficiently, resulting in less fuel usage and extended maintenance
intervals that can translate directly into bottom-line savings for
"The 2011 Super Duty is not only the most powerful, most capable and
fuel-efficient heavy-duty pickup truck on the road, it performs the
tough jobs with even more efficiency than ever before," said Doug Scott,
truck group marketing manager. "Customers can be confident that Super
Duty’s class-leading capability comes with Ford’s ‘and solution’ of
best-in-class fuel economy."
All-new diesel and gas engine powertrains are the backbone of the
2011 Super Duty’s best-in-class towing (26,400 pounds for F-550 chassis
cab with fifth-wheel hitch) and payload capability (6,520 pounds for
F-350 dual rear-wheel pickup). The Ford-designed, Ford-engineered and
Ford-built 6.7-liter Power Stroke V-8 turbocharged diesel engine
produces best-in-class 735 ft.-lb. of torque at 1,600 rpm and
best-in-class 390 horsepower at 2,800 rpm. The new engine is compatible
up to B20 biodiesel fuel as well.
The new 6.2-liter V-8 gasoline engine also boasts best-in-class
numbers of 405 ft.-lb. of torque at 4,500 rpm and 385 horsepower at
5,500 rpm. The new engine is E85 compatible.
Mated to each engine is the all-new 6R140 heavy-duty TorqShift
six-speed automatic transmission. The added feature content and overall
efficiency of the transmission are the main reasons for the improved
fuel economy. The all-new 2011 Ford F-Series Super Duty equipped with
the 6.7-liter Power Stroke diesel averages an 18 percent improvement
for pickup models and up to 25 percent improvement for chassis cabs
versus 2010 models. Trucks equipped with new base 6.2-liter V-8 gas
engine average a 15 percent improvement versus 2010 models.
"The new transmission is a ‘clean-sheet’ design, developed
specifically to handle the significantly increased torque produced by
the new diesel engine and the higher rotational speeds produced by the
new gas engine, and to deliver the power to the wheels seamlessly and
efficiently for heavy-duty truck customers," said Al Bruck,
transmission engineering manager. "Each system and component was
scrutinized to deliver optimum performance."
Here’s a closer look at what was achieved and the benefits to the
- New torque converter that locks at a far lower rpm than
the competition: The new, stronger torque converter is core to
the improved transmission performance. One key component is the
long-travel turbine damper that allows the transmission to lock earlier,
at a lower rpm, which translates to less slip and more fuel
efficiency. The new transmission locks down to 900 rpm, which is about
200 rpm less than the outgoing product and more than 100 rpm less
than competitors. The second key component of the torque converter is
the closed-piston design. This design allows for better control of the
lock-up clutch, which enables controlled converter clutch slip during
lock-to-lock upshifts that are seamless to the customer.
““ Customer fuel economy benefit: Locked
converter operation at lower speeds means less wasted heat energy and
better fuel economy.
- Optimized shift and converter lock-up schedule:
After analyzing the entire shift schedule, Ford calibration engineers
fine-tuned it by measuring and optimizing the fuel flow. The system
recognizes light or heavy throttle use, and puts the transmission in the
right gear for best performance and efficiency. The entire operating
range has been optimized to get the best fuel economy by locking up
the converter as soon as possible and as much as possible.
““ Customer fuel economy benefit: Optimizing the
shift schedule and lock schedule ensures customers automatically
operate in the most efficient gears and save fuel.
- Gearing and double-overdrive: The 6R140
transmission has a ratio span of about 5.9, which is quite a bit wider
than competitors. This wider span means the transmission has a deeper
first gear that allows customers to get the load moving quicker, and a
tall overdrive ratio for good highway efficiency. While the gearing
itself is important, the key to overall efficiency is matching that
gearing to the correct axle. With the diesel engine, up to four axle
ratios are available on the pickups ““ 3.31, 3.55, 3.73 and 4.30.
Matching up the gearing with the right axles means better overall
““ Customer fuel economy benefit: The
double-overdrive gear means even if a customer gets a downshift on the
highway, the transmission remains in overdrive. Also, the F-450 pickup
went from a 4.88 axle to a 4.30 axle at launch for the 2011 model
mated to the wide ratio span of the transmission. This and other
optimizations mean the F-450 now has about a 30 percent improvement in
- Optimized pumping pressure: A certain amount of
pressure is required to hold the clutches together so they don’t slip.
The trick is to have the right amount of pressure to do the job. Too
much pressure wastes fuel. The solution is to optimize the size of the
pump and precisely control the pressure for all operating conditions.
““ Customer fuel economy benefit: At highway
speeds, for example, the line pressure is reduced, which helps save
fuel. The system maintains the right amount of pressure for any given
speed range. The less energy needed for internal pump pressure means
less fuel used.
- Optimized drainback to reduce spin losses: A
main objective is to get the fluid through the main barrel to lubricate
and cool components, and get it back to the sump as quickly as
possible. This reduces windage and parasitic loss. The clutch friction
plates were designed to allow fluid to flow through them efficiently
for cooling and reduced drag. Clutch housings, connecting shells and
the main case housing were optimized to quickly drain the fluid out of
rotating components and back into the sump.
““ Customer fuel economy benefit: Fewer parasitic
losses due to reduced churning of fluid increases fuel economy.
- Warmer operating temperature: Tied in with spin
losses, the 6R140 cooling system has been optimized to allow for the
proper amount of cooling when towing heavy loads in high ambient
temperatures, while running at an overall higher stabilized temperature.
This higher stabilized temperature lowers the viscosity and helps the
fluid flow more easily, which reduces parasitic losses and saves
fuel. The fluid also warms up faster because it does not flow to the
cooling circuit until properly warmed up. Faster warm-up also reduces
overall parasitic losses.
““ Customer fuel economy benefit: Fewer parasitic
losses due to reduced fluid viscosity translates to less internal
drag on the system and increases fuel economy.
Lighter, more efficient than competition
The 6R140 transmission is about 25 pounds lighter than those of
competitors. The new engines are lighter than the outgoing products as
well, which altogether means much more efficient power flow on a
pound-for-pound basis. The 6R140 also has a 150,000-mile fluid change
interval, which is 2½ times greater than the outgoing product. A
patent-pending high-efficiency dual-media filter is the main reason for
the extended maintenance interval, which is another savings for
Cleanest Power Stroke ever
The new 6.7-liter Power Stroke V-8 turbocharged diesel employs an
aftertreatment system to help comply with 2010 federal regulations to
reduce NOx levels in diesel emissions by more than 80 percent compared
with the previous standard. The Ford aftertreatment system is a
three-stage process; a key component is the use of Diesel Exhaust Fluid
Injection of DEF to reduce NOx is a proven technology that’s been
used throughout the automotive industry. Unlike other strategies used to
control NOx, the DEF system allows the diesel engine to run at its
optimum range in terms of fuel mixture. Some systems require the engine
to run richer ““ which can be harmful to diesel engines ““ in order to
control the NOx.
The aftertreatment system works like this:
Step One: Cleaning and Heating ““ The first
step in cleaning the diesel exhaust occurs when the exhaust stream
enters the Diesel Oxidation Catalyst (DOC). The role of the DOC is
twofold. First, it converts and oxidizes hydrocarbons into water and
carbon dioxide. This conversion happens at about 250 degrees Celsius.
Second, the DOC is used to provide and promote heat, using specific
engine management strategies, into the exhaust system. Through
appropriate thermal management, this heat increases the conversion
efficiency of the downstream subsystems in reducing emissions.
Step Two: Knocking Out the NOx ““ The next
step in the process is what’s known as Selective Catalytic Reduction
(SCR). In this process, the NOx in the exhaust stream is converted into
water and inert nitrogen, which is present in the atmosphere and
harmless. Before the exhaust gas enters the SCR chamber, it is dosed
with DEF, an aqueous solution that is approximately 67.5 percent water
and 32.5 percent pure urea.
When heated, the DEF splits into ammonia and carbon dioxide. These
molecules are atomized and vaporized, then enter a mixer that resembles a
corkscrew. This twist mixer evenly distributes the ammonia within the
exhaust flow. The ammonia enters the SCR module, which contains a
catalyzed substrate, and through chemical reactions combines and
converts the NOx and ammonia into the harmless inert nitrogen and water.
Dosing occurs between 200 and 500 degrees Celsius.
Step Three: Scrubbing Away the Soot ““ The
final part of the cleansing system for the diesel exhaust gas involves
the Diesel Particulate Filter (DPF). The DPF traps any remaining soot,
which is then periodically burned away, known as regenerating, when
sensors detect the trap is full. The regeneration process sees
temperatures in excess of 600 degrees Celsius to burn away soot.
This industry-proven technology ensures that the new 6.7-liter diesel
is the cleanest Power Stroke ever, as well as the most
"Having this diesel designed in-house at Ford meant we were able to
work on optimizations and refinements right from the start," said Tim
Ogilvie, vehicle energy supervisor. "We’re able to deliver to customers
a more refined, more fuel-efficient Super Duty, with class-leading
torque and horsepower and the class-leading capability they demand."
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